diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
index aa0b6a2f64b..0f6d464f4a1 100644
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@@ -96,6 +96,9 @@ NOTICE @BenHenning
 # Language configuration files.
 config/**/languages/*.textproto @BenHenning
 
+# Configuration for KitKat-specific curated builds.
+config/kitkat_main_dex_class_list.txt @BenHenning
+
 #####################################################################################
 #                                    app module                                     #
 #####################################################################################
diff --git a/.github/workflows/build_tests.yml b/.github/workflows/build_tests.yml
index b827f77733b..4fa60d192e0 100644
--- a/.github/workflows/build_tests.yml
+++ b/.github/workflows/build_tests.yml
@@ -22,6 +22,8 @@ jobs:
       CACHE_DIRECTORY: ~/.bazel_cache
     steps:
       - uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
 
       - name: Set up JDK 9
         uses: actions/setup-java@v1
@@ -130,16 +132,36 @@ jobs:
         run: |
           bazel build -- //:oppia
 
-      - name: Copy Oppia APK for uploading
-        run: cp $GITHUB_WORKSPACE/bazel-bin/oppia.apk /home/runner/work/oppia-android/oppia-android/
+      # Note that caching only works on non-forks.
+      - name: Build Oppia KitKat binary (with caching, non-fork only)
+        if: ${{ env.ENABLE_CACHING == 'true' && github.event.pull_request.head.repo.full_name == 'oppia/oppia-android' }}
+        env:
+          BAZEL_REMOTE_CACHE_URL: ${{ secrets.BAZEL_REMOTE_CACHE_URL }}
+        run: |
+          bazel build --remote_http_cache=$BAZEL_REMOTE_CACHE_URL --google_credentials=./config/oppia-dev-workflow-remote-cache-credentials.json -- //:oppia_kitkat
+
+      - name: Build Oppia binary KitKat (without caching, or on a fork)
+        if: ${{ env.ENABLE_CACHING == 'false' || github.event.pull_request.head.repo.full_name != 'oppia/oppia-android' }}
+        run: |
+          bazel build -- //:oppia_kitkat
+
+      - name: Copy Oppia dev APKs for uploading
+        run: |
+          cp $GITHUB_WORKSPACE/bazel-bin/oppia.apk /home/runner/work/oppia-android/oppia-android/
+          cp $GITHUB_WORKSPACE/bazel-bin/oppia_kitkat.apk /home/runner/work/oppia-android/oppia-android/
 
       - uses: actions/upload-artifact@v2
         with:
           name: oppia-bazel.apk
           path: /home/runner/work/oppia-android/oppia-android/oppia.apk
 
+      - uses: actions/upload-artifact@v2
+        with:
+          name: oppia-bazel-kitkat.apk
+          path: /home/runner/work/oppia-android/oppia-android/oppia_kitkat.apk
+
   build_oppia_dev_aab:
-    name: Build Oppia AAB (developer flavor)
+    name: Build Oppia AAB (developer flavors)
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
@@ -259,16 +281,36 @@ jobs:
         run: |
           bazel build -- //:oppia_dev
 
-      - name: Copy Oppia APK for uploading
-        run: cp $GITHUB_WORKSPACE/bazel-bin/oppia_dev.aab /home/runner/work/oppia-android/oppia-android/
+      # Note that caching only works on non-forks.
+      - name: Build Oppia developer KitKat AAB (with caching, non-fork only)
+        if: ${{ env.ENABLE_CACHING == 'true' && github.event.pull_request.head.repo.full_name == 'oppia/oppia-android' }}
+        env:
+          BAZEL_REMOTE_CACHE_URL: ${{ secrets.BAZEL_REMOTE_CACHE_URL }}
+        run: |
+          bazel build --remote_http_cache=$BAZEL_REMOTE_CACHE_URL --google_credentials=./config/oppia-dev-workflow-remote-cache-credentials.json -- //:oppia_dev_kitkat
+
+      - name: Build Oppia developer KitKat AAB (without caching, or on a fork)
+        if: ${{ env.ENABLE_CACHING == 'false' || github.event.pull_request.head.repo.full_name != 'oppia/oppia-android' }}
+        run: |
+          bazel build -- //:oppia_dev_kitkat
+
+      - name: Copy Oppia developer AABs for uploading
+        run: |
+          cp $GITHUB_WORKSPACE/bazel-bin/oppia_dev.aab /home/runner/work/oppia-android/oppia-android/
+          cp $GITHUB_WORKSPACE/bazel-bin/oppia_dev_kitkat.aab /home/runner/work/oppia-android/oppia-android/
 
       - uses: actions/upload-artifact@v2
         with:
           name: oppia_dev.aab
           path: /home/runner/work/oppia-android/oppia-android/oppia_dev.aab
 
+      - uses: actions/upload-artifact@v2
+        with:
+          name: oppia_dev_kitkat.aab
+          path: /home/runner/work/oppia-android/oppia-android/oppia_dev_kitkat.aab
+
   build_oppia_alpha_aab:
-    name: Build Oppia AAB (alpha flavor)
+    name: Build Oppia AAB (alpha flavors)
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
@@ -388,10 +430,30 @@ jobs:
         run: |
           bazel build --compilation_mode=opt -- //:oppia_alpha
 
-      - name: Copy Oppia APK for uploading
-        run: cp $GITHUB_WORKSPACE/bazel-bin/oppia_alpha.aab /home/runner/work/oppia-android/oppia-android/
+      # Note that caching only works on non-forks.
+      - name: Build Oppia alpha KitKat AAB (with caching, non-fork only)
+        if: ${{ env.ENABLE_CACHING == 'true' && github.event.pull_request.head.repo.full_name == 'oppia/oppia-android' }}
+        env:
+          BAZEL_REMOTE_CACHE_URL: ${{ secrets.BAZEL_REMOTE_CACHE_URL }}
+        run: |
+          bazel build --compilation_mode=opt --remote_http_cache=$BAZEL_REMOTE_CACHE_URL --google_credentials=./config/oppia-dev-workflow-remote-cache-credentials.json -- //:oppia_alpha_kitkat
+
+      - name: Build Oppia alpha KitKat AAB (without caching, or on a fork)
+        if: ${{ env.ENABLE_CACHING == 'false' || github.event.pull_request.head.repo.full_name != 'oppia/oppia-android' }}
+        run: |
+          bazel build --compilation_mode=opt -- //:oppia_alpha_kitkat
+
+      - name: Copy Oppia alpha AABs for uploading
+        run: |
+          cp $GITHUB_WORKSPACE/bazel-bin/oppia_alpha.aab /home/runner/work/oppia-android/oppia-android/
+          cp $GITHUB_WORKSPACE/bazel-bin/oppia_alpha_kitkat.aab /home/runner/work/oppia-android/oppia-android/
 
       - uses: actions/upload-artifact@v2
         with:
           name: oppia_alpha.aab
           path: /home/runner/work/oppia-android/oppia-android/oppia_alpha.aab
+
+      - uses: actions/upload-artifact@v2
+        with:
+          name: oppia_alpha_kitkat.aab
+          path: /home/runner/work/oppia-android/oppia-android/oppia_alpha_kitkat.aab
diff --git a/BUILD.bazel b/BUILD.bazel
index 845129a3402..b6eefe19198 100644
--- a/BUILD.bazel
+++ b/BUILD.bazel
@@ -1,6 +1,10 @@
 # TODO(#1532): Rename file to 'BUILD' post-Gradle.
 
-load("//:build_flavors.bzl", "AVAILABLE_FLAVORS", "define_oppia_binary_flavor")
+load("//:build_flavors.bzl", "AVAILABLE_FLAVORS", "define_oppia_aab_binary_flavor", "transform_android_manifest")
+load("//:version.bzl", "MAJOR_VERSION", "MINOR_VERSION", "OPPIA_DEV_KITKAT_VERSION_CODE", "OPPIA_DEV_VERSION_CODE")
+
+# This is exported here since config/ isn't a Bazel package.
+exports_files(["config/kitkat_main_dex_class_list.txt"])
 
 # Corresponds to being accessible to all Oppia targets. This should be used for production APIs &
 # modules that may be used both in production targets and in tests.
@@ -68,28 +72,66 @@ package_group(
 )
 
 # TODO(#1640): Move binary manifest to top-level package post-Gradle.
-android_binary(
-    name = "oppia",
-    custom_package = "org.oppia.android",
-    enable_data_binding = True,
-    manifest = "//app:src/main/AndroidManifest.xml",
-    manifest_values = {
-        "applicationId": "org.oppia.android",
-        "minSdkVersion": "19",
-        "targetSdkVersion": "29",
-        "versionCode": "0",
-        "versionName": "0.1-alpha",
-    },
-    multidex = "native",
-    deps = [
-        "//app",
-    ],
-)
+[
+    transform_android_manifest(
+        name = "oppia_apk_%s_transformed_manifest" % apk_flavor_metadata["flavor"],
+        build_flavor = apk_flavor_metadata["flavor"],
+        input_file = "//app:src/main/AndroidManifest.xml",
+        major_version = MAJOR_VERSION,
+        minor_version = MINOR_VERSION,
+        output_file = "AndroidManifest_transformed_%s.xml" % apk_flavor_metadata["flavor"],
+        version_code = apk_flavor_metadata["version_code"],
+    )
+    for apk_flavor_metadata in [
+        {
+            "flavor": "oppia",
+            "version_code": OPPIA_DEV_VERSION_CODE,
+        },
+        {
+            "flavor": "oppia_kitkat",
+            "version_code": OPPIA_DEV_KITKAT_VERSION_CODE,
+        },
+    ]
+]
+
+[
+    android_binary(
+        name = apk_flavor_metadata["flavor"],
+        custom_package = "org.oppia.android",
+        enable_data_binding = True,
+        main_dex_list = apk_flavor_metadata.get("main_dex_list"),
+        manifest = "oppia_apk_%s_transformed_manifest" % apk_flavor_metadata["flavor"],
+        manifest_values = {
+            "applicationId": "org.oppia.android",
+            "minSdkVersion": "%d" % apk_flavor_metadata["min_sdk_version"],
+            "targetSdkVersion": "%d" % apk_flavor_metadata["target_sdk_version"],
+        },
+        multidex = apk_flavor_metadata["multidex"],
+        deps = [
+            "//app",
+        ],
+    )
+    for apk_flavor_metadata in [
+        {
+            "flavor": "oppia",
+            "min_sdk_version": 21,
+            "multidex": "native",
+            "target_sdk_version": 29,
+        },
+        {
+            "flavor": "oppia_kitkat",
+            "main_dex_list": "//:config/kitkat_main_dex_class_list.txt",
+            "min_sdk_version": 19,
+            "multidex": "manual_main_dex",
+            "target_sdk_version": 29,
+        },
+    ]
+]
 
 # Define all binary flavors that can be built. Note that these are AABs, not APKs, and can be
 # be installed on a local device or emulator using a 'bazel run' command like so:
 #  bazel run //:install_oppia_dev
 [
-    define_oppia_binary_flavor(flavor = flavor)
+    define_oppia_aab_binary_flavor(flavor = flavor)
     for flavor in AVAILABLE_FLAVORS
 ]
diff --git a/app/BUILD.bazel b/app/BUILD.bazel
index fba131c801b..caf40076824 100644
--- a/app/BUILD.bazel
+++ b/app/BUILD.bazel
@@ -529,7 +529,6 @@ android_library(
 # Library for layout resource files.
 android_library(
     name = "databinding_resources",
-    srcs = BINDING_ADAPTERS,
     custom_package = "org.oppia.android.app.databinding",
     enable_data_binding = True,
     exports_manifest = True,
@@ -685,6 +684,7 @@ android_library(
         "//third_party:androidx_lifecycle_lifecycle-livedata-ktx",
         "//third_party:circularimageview_circular_image_view",
         "//third_party:com_google_android_material_material",
+        "//third_party:de_hdodenhof_circleimageview",
         "//third_party:io_github_chaosleung_pinview",
         "//utility",
         "//utility/src/main/java/org/oppia/android/util/system:oppia_clock",
diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index c5f15f4bfc3..7d433c0fea2 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -5,6 +5,8 @@
 
   <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
   <uses-permission android:name="android.permission.INTERNET" />
+  <uses-permission android:name="android.permission.WAKE_LOCK" />
+
   <!-- TODO(#56): Reenable landscape support. -->
   <application
     android:name=".app.application.OppiaApplication"
diff --git a/app/src/main/java/org/oppia/android/app/application/OppiaApplication.kt b/app/src/main/java/org/oppia/android/app/application/OppiaApplication.kt
index 7ef0f1bfde9..5eafca3585c 100644
--- a/app/src/main/java/org/oppia/android/app/application/OppiaApplication.kt
+++ b/app/src/main/java/org/oppia/android/app/application/OppiaApplication.kt
@@ -1,7 +1,10 @@
 package org.oppia.android.app.application
 
+import android.annotation.SuppressLint
 import android.app.Application
+import android.os.Build
 import androidx.appcompat.app.AppCompatActivity
+import androidx.appcompat.app.AppCompatDelegate
 import androidx.multidex.MultiDexApplication
 import androidx.work.Configuration
 import androidx.work.WorkManager
@@ -29,8 +32,17 @@ class OppiaApplication :
 
   override fun getApplicationInjector(): ApplicationInjector = component
 
+  @SuppressLint("ObsoleteSdkInt") // Incorrect warning.
   override fun onCreate() {
     super.onCreate()
+    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
+      // Ensure vector drawables can be properly loaded on KitKat devices. Note that this can
+      // introduce memory issues, but it's an easier-to-maintain solution that replacing all image
+      // binding with custom hook-ins (especially when it comes to databinding which isn't
+      // configurable in how it loads drawables), or building a custom vector drawable->PNG pipeline
+      // in Bazel.
+      AppCompatDelegate.setCompatVectorFromResourcesEnabled(true)
+    }
     FirebaseApp.initializeApp(applicationContext)
     WorkManager.initialize(applicationContext, workManagerConfiguration)
     component.getApplicationStartupListeners().forEach(ApplicationStartupListener::onCreate)
diff --git a/app/src/main/java/org/oppia/android/app/databinding/ImageViewBindingAdapters.java b/app/src/main/java/org/oppia/android/app/databinding/ImageViewBindingAdapters.java
index 710098a0dee..818fa574dec 100644
--- a/app/src/main/java/org/oppia/android/app/databinding/ImageViewBindingAdapters.java
+++ b/app/src/main/java/org/oppia/android/app/databinding/ImageViewBindingAdapters.java
@@ -10,116 +10,26 @@
 import com.bumptech.glide.load.DataSource;
 import com.bumptech.glide.load.engine.GlideException;
 import com.bumptech.glide.request.RequestListener;
-import com.bumptech.glide.request.RequestOptions;
 import com.bumptech.glide.request.target.Target;
 import org.oppia.android.R;
-import org.oppia.android.app.model.LessonThumbnailGraphic;
 import org.oppia.android.app.model.ProfileAvatar;
 
 /** Holds all custom binding adapters that bind to [ImageView]. */
 public final class ImageViewBindingAdapters {
-  /**
-   * Allows binding drawables to an [ImageView] via "android:src".
-   * Reference: https://stackoverflow.com/a/35809319/3689782.
-   */
-  @BindingAdapter("android:src")
-  public static void setImageDrawable(@NonNull ImageView imageView, String imageUrl) {
-    RequestOptions requestOptions = new RequestOptions().placeholder(R.drawable.review_placeholder);
-    Glide.with(imageView.getContext())
-        .load(imageUrl)
-        .apply(requestOptions)
-        .into(imageView);
-  }
-
-  /**
-   * Allows binding drawables to an [ImageView] via "android:src".
-   * Reference: https://stackoverflow.com/a/35809319/3689782.
-   */
-  @BindingAdapter("android:src")
-  public static void setImageDrawable(
+  @BindingAdapter("app:srcCompat")
+  public static void setImageDrawableCompat(
       @NonNull ImageView imageView,
       @DrawableRes int drawableResourceId
   ) {
     imageView.setImageResource(drawableResourceId);
   }
 
-  /**
-   * Binds the specified [LessonThumbnailGraphic] as the source for the [ImageView].
-   * <p/>
-   * The view should be specified to have no width/height (when sized in a constraint layout), and
-   * use centerCrop for the image to appear correctly.
-   */
-  @BindingAdapter("android:src")
-  public static void setImageDrawable(
-      ImageView imageView,
-      LessonThumbnailGraphic thumbnailGraphic
+  @BindingAdapter("app:srcCompat")
+  public static void setImageDrawableCompat(
+      @NonNull ImageView imageView,
+      Drawable drawable
   ) {
-    int drawableResourceId;
-    switch (thumbnailGraphic) {
-      case BAKER:
-        drawableResourceId = R.drawable.lesson_thumbnail_graphic_baker;
-        break;
-      case CHILD_WITH_BOOK:
-        drawableResourceId = R.drawable.lesson_thumbnail_graphic_child_with_book;
-        break;
-      case CHILD_WITH_CUPCAKES:
-        drawableResourceId = R.drawable.lesson_thumbnail_graphic_child_with_cupcakes;
-        break;
-      case CHILD_WITH_FRACTIONS_HOMEWORK:
-        drawableResourceId = R.drawable.lesson_thumbnail_graphic_child_with_fractions_homework;
-        break;
-      case DUCK_AND_CHICKEN:
-        drawableResourceId = R.drawable.lesson_thumbnail_graphic_duck_and_chicken;
-        break;
-      case PERSON_WITH_PIE_CHART:
-        drawableResourceId = R.drawable.lesson_thumbnail_graphic_person_with_pie_chart;
-        break;
-      case IDENTIFYING_THE_PARTS_OF_A_FRACTION:
-        drawableResourceId = R.drawable.topic_fractions_01;
-        break;
-      case WRITING_FRACTIONS:
-        drawableResourceId = R.drawable.topic_fractions_02;
-        break;
-      case EQUIVALENT_FRACTIONS:
-        drawableResourceId = R.drawable.topic_fractions_03;
-        break;
-      case MIXED_NUMBERS_AND_IMPROPER_FRACTIONS:
-        drawableResourceId = R.drawable.topic_fractions_04;
-        break;
-      case COMPARING_FRACTIONS:
-        drawableResourceId = R.drawable.topic_fractions_05;
-        break;
-      case ADDING_AND_SUBTRACTING_FRACTIONS:
-        drawableResourceId = R.drawable.topic_fractions_06;
-        break;
-      case MULTIPLYING_FRACTIONS:
-        drawableResourceId = R.drawable.topic_fractions_07;
-        break;
-      case DIVIDING_FRACTIONS:
-        drawableResourceId = R.drawable.topic_fractions_08;
-        break;
-      case DERIVE_A_RATIO:
-        drawableResourceId = R.drawable.topic_ratios_01;
-        break;
-      case WHAT_IS_A_FRACTION:
-        drawableResourceId = R.drawable.topic_fractions_01;
-        break;
-      case FRACTION_OF_A_GROUP:
-        drawableResourceId = R.drawable.topic_fractions_02;
-        break;
-      case ADDING_FRACTIONS:
-        drawableResourceId = R.drawable.topic_fractions_03;
-        break;
-      case MIXED_NUMBERS:
-        drawableResourceId = R.drawable.topic_fractions_04;
-        break;
-      default:
-        drawableResourceId = R.drawable.topic_fractions_01;
-    }
-    setImageDrawable(
-        imageView,
-        drawableResourceId
-    );
+    imageView.setImageDrawable(drawable);
   }
 
   /**
diff --git a/app/src/main/java/org/oppia/android/app/databinding/TextViewBindingAdapters.java b/app/src/main/java/org/oppia/android/app/databinding/TextViewBindingAdapters.java
index e701a8cf20b..00b2abb0255 100644
--- a/app/src/main/java/org/oppia/android/app/databinding/TextViewBindingAdapters.java
+++ b/app/src/main/java/org/oppia/android/app/databinding/TextViewBindingAdapters.java
@@ -3,6 +3,7 @@
 import android.app.Activity;
 import android.content.Context;
 import android.content.ContextWrapper;
+import android.graphics.drawable.Drawable;
 import android.view.View;
 import android.widget.TextView;
 import androidx.annotation.NonNull;
@@ -45,6 +46,17 @@ public static void setProfileLastVisitedText(@NonNull TextView textView, long ti
     textView.setText(profileLastVisited);
   }
 
+  /** Binds an AndroidX KitKat-compatible drawable end to the specified text view. */
+  @BindingAdapter("app:drawableEndCompat")
+  public static void setDrawableEndCompat(
+      @NonNull TextView imageView,
+      Drawable drawable
+  ) {
+    imageView.setCompoundDrawablesRelativeWithIntrinsicBounds(
+        /* start= */ null, /* top= */ null, /* end= */ drawable, /* bottom=*/ null
+    );
+  }
+
   private static String getTimeAgo(View view, long lastVisitedTimestamp) {
     long timeStampMillis = ensureTimestampIsInMilliseconds(lastVisitedTimestamp);
     long currentTimeMillis = getOppiaClock(view).getCurrentTimeMs();
diff --git a/app/src/main/java/org/oppia/android/app/drawer/NavigationDrawerFragmentPresenter.kt b/app/src/main/java/org/oppia/android/app/drawer/NavigationDrawerFragmentPresenter.kt
index 3f0525734ab..709d7f5af05 100644
--- a/app/src/main/java/org/oppia/android/app/drawer/NavigationDrawerFragmentPresenter.kt
+++ b/app/src/main/java/org/oppia/android/app/drawer/NavigationDrawerFragmentPresenter.kt
@@ -1,6 +1,5 @@
 package org.oppia.android.app.drawer
 
-import android.os.Build
 import android.view.LayoutInflater
 import android.view.MenuItem
 import android.view.View
@@ -15,6 +14,7 @@ import androidx.lifecycle.LiveData
 import androidx.lifecycle.Observer
 import androidx.lifecycle.Transformations
 import com.google.android.material.navigation.NavigationView
+import com.google.common.base.Optional
 import org.oppia.android.R
 import org.oppia.android.app.administratorcontrols.AdministratorControlsActivity
 import org.oppia.android.app.devoptions.DeveloperOptionsStarter
@@ -40,7 +40,6 @@ import org.oppia.android.domain.topic.TopicController
 import org.oppia.android.util.data.AsyncResult
 import org.oppia.android.util.data.DataProviders.Companion.toLiveData
 import org.oppia.android.util.statusbar.StatusBarColor
-import java.util.Optional
 import javax.inject.Inject
 
 const val NAVIGATION_PROFILE_ID_ARGUMENT_KEY =
@@ -98,29 +97,26 @@ class NavigationDrawerFragmentPresenter @Inject constructor(
 
   // TODO(#3382): Remove debug only code from prod build (also check imports, constructor and drawer_fragment.xml)
   private fun setIfDeveloperOptionsMenuItemListener() {
-    // TODO(#3383): Find a way to make this work below N
-    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
-      developerOptionsStarter.ifPresent { starter ->
-        getFooterViewModel().isDebugMode.set(true)
-        binding.developerOptionsLinearLayout.setOnClickListener {
-          if (getFooterViewModel().isDeveloperOptionsSelected.get() == true) {
-            drawerLayout.closeDrawers()
-            return@setOnClickListener
-          }
-          uncheckAllMenuItemsWhenAdministratorControlsOrDeveloperOptionsIsSelected()
-          drawerLayout.closeDrawers()
-          getFooterViewModel().isDeveloperOptionsSelected.set(true)
-          val intent = starter.createIntent(activity, internalProfileId)
-          fragment.activity!!.startActivity(intent)
-          if (previousMenuItemId == 0) fragment.activity!!.finish()
-          else if (previousMenuItemId != null &&
-            NavigationDrawerItem.valueFromNavId(previousMenuItemId!!) !=
-            NavigationDrawerItem.HOME
-          ) {
-            fragment.activity!!.finish()
-          }
+    developerOptionsStarter.asSet().forEach { starter ->
+      getFooterViewModel().isDebugMode.set(true)
+      binding.developerOptionsLinearLayout.setOnClickListener {
+        if (getFooterViewModel().isDeveloperOptionsSelected.get() == true) {
           drawerLayout.closeDrawers()
+          return@setOnClickListener
+        }
+        uncheckAllMenuItemsWhenAdministratorControlsOrDeveloperOptionsIsSelected()
+        drawerLayout.closeDrawers()
+        getFooterViewModel().isDeveloperOptionsSelected.set(true)
+        val intent = starter.createIntent(activity, internalProfileId)
+        fragment.activity!!.startActivity(intent)
+        if (previousMenuItemId == 0) fragment.activity!!.finish()
+        else if (previousMenuItemId != null &&
+          NavigationDrawerItem.valueFromNavId(previousMenuItemId!!) !=
+          NavigationDrawerItem.HOME
+        ) {
+          fragment.activity!!.finish()
         }
+        drawerLayout.closeDrawers()
       }
     }
   }
diff --git a/app/src/main/res/layout-land/hints_summary.xml b/app/src/main/res/layout-land/hints_summary.xml
index c1dcba67a30..2b654d0c309 100644
--- a/app/src/main/res/layout-land/hints_summary.xml
+++ b/app/src/main/res/layout-land/hints_summary.xml
@@ -84,7 +84,7 @@
           android:layout_gravity="center_vertical"
           android:contentDescription="@{viewModel.computeHintListDropDownIconContentDescription()}"
           android:padding="8dp"
-          android:src="@drawable/ic_arrow_drop_down_black_24dp"
+          app:srcCompat="@drawable/ic_arrow_drop_down_black_24dp"
           app:isRotationAnimationClockwise="@{isListExpanded}"
           app:rotationAnimationAngle="@{180f}" />
       </FrameLayout>
diff --git a/app/src/main/res/layout-land/lessons_chapter_view.xml b/app/src/main/res/layout-land/lessons_chapter_view.xml
index 3b7897fb411..d3fdbbca226 100644
--- a/app/src/main/res/layout-land/lessons_chapter_view.xml
+++ b/app/src/main/res/layout-land/lessons_chapter_view.xml
@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<layout xmlns:android="http://schemas.android.com/apk/res/android">
+<layout xmlns:android="http://schemas.android.com/apk/res/android"
+  xmlns:app="http://schemas.android.com/apk/res-auto">
 
   <data>
 
@@ -31,7 +32,7 @@
       android:layout_marginStart="16dp"
       android:layout_marginEnd="8dp"
       android:contentDescription="@{viewModel.computeChapterPlayStateIconContentDescription()}"
-      android:src="@{viewModel.chapterPlayState == ChapterPlayState.COMPLETED?@drawable/ic_check_24dp:@drawable/ic_pending_24dp}"
+      app:srcCompat="@{viewModel.chapterPlayState == ChapterPlayState.COMPLETED?@drawable/ic_check_24dp:@drawable/ic_pending_24dp}"
       android:visibility="@{(viewModel.chapterPlayState == ChapterPlayState.COMPLETED || viewModel.chapterPlayState == ChapterPlayState.IN_PROGRESS_SAVED)?View.VISIBLE : View.INVISIBLE}" />
 
     <TextView
diff --git a/app/src/main/res/layout-land/onboarding_fragment.xml b/app/src/main/res/layout-land/onboarding_fragment.xml
index 8d750098ad5..0cf84ae2c24 100644
--- a/app/src/main/res/layout-land/onboarding_fragment.xml
+++ b/app/src/main/res/layout-land/onboarding_fragment.xml
@@ -72,7 +72,7 @@
       android:minHeight="48dp"
       android:onClick="@{(v) -> presenter.clickOnNext()}"
       android:padding="12dp"
-      android:src="@drawable/ic_arrow_forward_black_24dp"
+      app:srcCompat="@drawable/ic_arrow_forward_black_24dp"
       android:visibility="@{viewModel.slideNumber != 3 ? View.VISIBLE: View.GONE, default=visible}"
       app:layout_constraintBottom_toBottomOf="parent"
       app:layout_constraintEnd_toEndOf="parent" />
diff --git a/app/src/main/res/layout-land/onboarding_slide.xml b/app/src/main/res/layout-land/onboarding_slide.xml
index ce316a794bd..3ac11c15768 100644
--- a/app/src/main/res/layout-land/onboarding_slide.xml
+++ b/app/src/main/res/layout-land/onboarding_slide.xml
@@ -29,7 +29,7 @@
         android:adjustViewBounds="true"
         android:importantForAccessibility="no"
         android:scaleType="fitXY"
-        android:src="@{viewModel.slideImage}"
+        app:srcCompat="@{viewModel.slideImage}"
         app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintDimensionRatio="H, 10:9"
         app:layout_constraintStart_toStartOf="parent"
diff --git a/app/src/main/res/layout-land/onboarding_slide_final.xml b/app/src/main/res/layout-land/onboarding_slide_final.xml
index 934c8ed5758..afec77e83e1 100644
--- a/app/src/main/res/layout-land/onboarding_slide_final.xml
+++ b/app/src/main/res/layout-land/onboarding_slide_final.xml
@@ -30,7 +30,7 @@
         android:adjustViewBounds="true"
         android:importantForAccessibility="no"
         android:scaleType="fitXY"
-        android:src="@drawable/ic_landscape_onboarding_3"
+        app:srcCompat="@drawable/ic_landscape_onboarding_3"
         app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintDimensionRatio="H, 10:9"
         app:layout_constraintStart_toStartOf="parent"
diff --git a/app/src/main/res/layout-land/profile_chooser_add_view.xml b/app/src/main/res/layout-land/profile_chooser_add_view.xml
index ca149ec25ff..71071ed8f22 100644
--- a/app/src/main/res/layout-land/profile_chooser_add_view.xml
+++ b/app/src/main/res/layout-land/profile_chooser_add_view.xml
@@ -33,7 +33,7 @@
         android:layout_width="72dp"
         android:layout_height="72dp"
         android:layout_marginBottom="8dp"
-        android:src="@drawable/ic_add_profile"
+        app:srcCompat="@{@drawable/ic_add_profile}"
         app:civ_border_color="@color/avatarBorder"
         app:civ_border_width="1dp" />
 
diff --git a/app/src/main/res/layout-land/profile_chooser_fragment.xml b/app/src/main/res/layout-land/profile_chooser_fragment.xml
index 3d9a06b1bc4..43d2939a6a7 100644
--- a/app/src/main/res/layout-land/profile_chooser_fragment.xml
+++ b/app/src/main/res/layout-land/profile_chooser_fragment.xml
@@ -33,7 +33,7 @@
           android:paddingStart="4dp"
           android:paddingTop="20dp"
           android:paddingEnd="20dp"
-          android:src="@drawable/ic_language_icon_grey_24dp"
+          app:srcCompat="@drawable/ic_language_icon_grey_24dp"
           android:visibility="gone"
           app:layout_constraintEnd_toEndOf="parent"
           app:layout_constraintTop_toTopOf="parent" />
@@ -117,7 +117,7 @@
         android:paddingTop="12dp"
         android:paddingEnd="16dp"
         android:paddingBottom="12dp"
-        android:src="@drawable/ic_settings_grey_48dp" />
+        app:srcCompat="@drawable/ic_settings_grey_48dp" />
     </LinearLayout>
   </androidx.constraintlayout.widget.ConstraintLayout>
 </layout>
diff --git a/app/src/main/res/layout-land/profile_progress_header.xml b/app/src/main/res/layout-land/profile_progress_header.xml
index 3607624b315..8e9cfdc89c2 100644
--- a/app/src/main/res/layout-land/profile_progress_header.xml
+++ b/app/src/main/res/layout-land/profile_progress_header.xml
@@ -39,7 +39,7 @@
       android:onClick="@{() -> viewModel.clickOnProfilePicture()}"
       android:paddingStart="12dp"
       android:paddingTop="12dp"
-      android:src="@drawable/rounded_white_background_with_shadow"
+      app:srcCompat="@drawable/rounded_white_background_with_shadow"
       app:layout_constraintBottom_toBottomOf="@+id/profile_edit_image"
       app:layout_constraintEnd_toEndOf="@+id/profile_edit_image" />
 
diff --git a/app/src/main/res/layout-land/question_player_fragment.xml b/app/src/main/res/layout-land/question_player_fragment.xml
index 02b7cbdcfa0..b90b0b24ffc 100644
--- a/app/src/main/res/layout-land/question_player_fragment.xml
+++ b/app/src/main/res/layout-land/question_player_fragment.xml
@@ -148,7 +148,7 @@
         android:layout_gravity="top|end"
         android:layout_margin="8dp"
         android:contentDescription="@string/new_hint_available"
-        android:src="@drawable/ic_dot_yellow_24dp"
+        app:srcCompat="@drawable/ic_dot_yellow_24dp"
         android:visibility="@{viewModel.isHintOpenedAndUnRevealed() ? View.VISIBLE : View.GONE}" />
 
       <ImageView
@@ -157,7 +157,7 @@
         android:layout_height="wrap_content"
         android:layout_margin="12dp"
         android:contentDescription="@string/show_hints_and_solution"
-        android:src="@drawable/ic_hint_bulb_white_24dp" />
+        app:srcCompat="@drawable/ic_hint_bulb_white_24dp" />
     </FrameLayout>
 
     <FrameLayout
diff --git a/app/src/main/res/layout-land/solution_summary.xml b/app/src/main/res/layout-land/solution_summary.xml
index 30f6bd21aec..f5063fb0f96 100644
--- a/app/src/main/res/layout-land/solution_summary.xml
+++ b/app/src/main/res/layout-land/solution_summary.xml
@@ -87,7 +87,7 @@
             android:padding="8dp"
             android:layout_gravity="center_vertical"
             android:contentDescription="@string/show_hide_solution_list"
-            android:src="@drawable/ic_arrow_drop_down_black_24dp"
+            app:srcCompat="@drawable/ic_arrow_drop_down_black_24dp"
             app:isRotationAnimationClockwise="@{isListExpanded}"
             app:rotationAnimationAngle="@{180f}" />
         </FrameLayout>
diff --git a/app/src/main/res/layout-land/story_chapter_view.xml b/app/src/main/res/layout-land/story_chapter_view.xml
index d1d43288657..be3a47b2989 100644
--- a/app/src/main/res/layout-land/story_chapter_view.xml
+++ b/app/src/main/res/layout-land/story_chapter_view.xml
@@ -95,7 +95,7 @@
             android:layout_marginEnd="8dp"
             android:layout_marginBottom="4dp"
             android:contentDescription="@{@string/chapter_completed}"
-            android:src="@drawable/ic_check_24dp"
+            app:srcCompat="@drawable/ic_check_24dp"
             android:visibility="@{viewModel.chapterSummary.chapterPlayState == ChapterPlayState.COMPLETED ? View.VISIBLE : View.GONE}"
             app:layout_constraintBottom_toBottomOf="parent"
             app:layout_constraintEnd_toEndOf="parent"
diff --git a/app/src/main/res/layout-land/topic_info_fragment.xml b/app/src/main/res/layout-land/topic_info_fragment.xml
index f42fd7673d2..007ec49262d 100644
--- a/app/src/main/res/layout-land/topic_info_fragment.xml
+++ b/app/src/main/res/layout-land/topic_info_fragment.xml
@@ -104,7 +104,7 @@
         android:layout_marginTop="24dp"
         android:layout_marginEnd="72dp"
         android:layout_marginBottom="32dp"
-        android:src="@{viewModel.downloadStatusIndicatorDrawableResourceId, default=@drawable/ic_available_offline_primary_24dp}"
+        app:srcCompat="@{viewModel.downloadStatusIndicatorDrawableResourceId, default=@drawable/ic_available_offline_primary_24dp}"
         app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toBottomOf="@+id/see_more_text_view" />
diff --git a/app/src/main/res/layout-land/topic_lessons_story_summary.xml b/app/src/main/res/layout-land/topic_lessons_story_summary.xml
index 09e92d066df..48ef7150074 100644
--- a/app/src/main/res/layout-land/topic_lessons_story_summary.xml
+++ b/app/src/main/res/layout-land/topic_lessons_story_summary.xml
@@ -135,7 +135,7 @@
               android:layout_height="wrap_content"
               android:layout_gravity="center_horizontal|bottom"
               android:contentDescription="@{isListExpanded ? @string/hide_chapter_list : @string/show_chapter_list}"
-              android:src="@drawable/ic_arrow_drop_down_black_24dp"
+              app:srcCompat="@drawable/ic_arrow_drop_down_black_24dp"
               app:isRotationAnimationClockwise="@{isListExpanded}"
               app:rotationAnimationAngle="@{180f}" />
           </FrameLayout>
diff --git a/app/src/main/res/layout-land/walkthrough_final_fragment.xml b/app/src/main/res/layout-land/walkthrough_final_fragment.xml
index c23c0c09f82..09ab8eeebb9 100644
--- a/app/src/main/res/layout-land/walkthrough_final_fragment.xml
+++ b/app/src/main/res/layout-land/walkthrough_final_fragment.xml
@@ -23,7 +23,7 @@
       android:layout_width="180dp"
       android:layout_height="180dp"
       android:layout_marginStart="28dp"
-      android:src="@drawable/ic_portrait_onboarding_0"
+      app:srcCompat="@drawable/ic_portrait_onboarding_0"
       app:layout_constraintBottom_toBottomOf="parent"
       app:layout_constraintStart_toStartOf="parent"
       app:layout_constraintTop_toTopOf="parent" />
diff --git a/app/src/main/res/layout-land/walkthrough_welcome_fragment.xml b/app/src/main/res/layout-land/walkthrough_welcome_fragment.xml
index 5ce14f69346..a34f65e94d7 100644
--- a/app/src/main/res/layout-land/walkthrough_welcome_fragment.xml
+++ b/app/src/main/res/layout-land/walkthrough_welcome_fragment.xml
@@ -57,7 +57,7 @@
         android:layout_width="180dp"
         android:layout_height="180dp"
         android:layout_marginStart="56dp"
-        android:src="@drawable/ic_portrait_onboarding_0"
+        app:srcCompat="@drawable/ic_portrait_onboarding_0"
         app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="parent" />
diff --git a/app/src/main/res/layout-sw600dp-land/hints_summary.xml b/app/src/main/res/layout-sw600dp-land/hints_summary.xml
index a9e5eb3639c..8f38a2a47a8 100644
--- a/app/src/main/res/layout-sw600dp-land/hints_summary.xml
+++ b/app/src/main/res/layout-sw600dp-land/hints_summary.xml
@@ -78,7 +78,7 @@
           android:layout_gravity="center_vertical"
           android:contentDescription="@{viewModel.computeHintListDropDownIconContentDescription()}"
           android:padding="8dp"
-          android:src="@drawable/ic_arrow_drop_down_black_24dp"
+          app:srcCompat="@drawable/ic_arrow_drop_down_black_24dp"
           app:isRotationAnimationClockwise="@{isListExpanded}"
           app:rotationAnimationAngle="@{180f}" />
       </FrameLayout>
diff --git a/app/src/main/res/layout-sw600dp-land/onboarding_fragment.xml b/app/src/main/res/layout-sw600dp-land/onboarding_fragment.xml
index 1f018a5b7a7..54be918fb4d 100644
--- a/app/src/main/res/layout-sw600dp-land/onboarding_fragment.xml
+++ b/app/src/main/res/layout-sw600dp-land/onboarding_fragment.xml
@@ -75,7 +75,7 @@
         android:minHeight="48dp"
         android:onClick="@{(v) -> presenter.clickOnNext()}"
         android:scaleType="center"
-        android:src="@drawable/ic_arrow_forward_black_24dp"
+        app:srcCompat="@drawable/ic_arrow_forward_black_24dp"
         android:visibility="@{viewModel.slideNumber != 3 ? View.VISIBLE: View.GONE, default=visible}"
         app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintEnd_toEndOf="parent"
diff --git a/app/src/main/res/layout-sw600dp-land/onboarding_slide.xml b/app/src/main/res/layout-sw600dp-land/onboarding_slide.xml
index 2e4497cf4b8..d583edeb5eb 100644
--- a/app/src/main/res/layout-sw600dp-land/onboarding_slide.xml
+++ b/app/src/main/res/layout-sw600dp-land/onboarding_slide.xml
@@ -28,7 +28,7 @@
         android:layout_height="0dp"
         android:adjustViewBounds="true"
         android:importantForAccessibility="no"
-        android:src="@{viewModel.slideImage}"
+        app:srcCompat="@{viewModel.slideImage}"
         app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintDimensionRatio="40:39"
         app:layout_constraintStart_toStartOf="parent"
diff --git a/app/src/main/res/layout-sw600dp-land/onboarding_slide_final.xml b/app/src/main/res/layout-sw600dp-land/onboarding_slide_final.xml
index 3944fb465ae..c3b3095228c 100644
--- a/app/src/main/res/layout-sw600dp-land/onboarding_slide_final.xml
+++ b/app/src/main/res/layout-sw600dp-land/onboarding_slide_final.xml
@@ -29,7 +29,7 @@
         android:layout_height="0dp"
         android:adjustViewBounds="true"
         android:importantForAccessibility="no"
-        android:src="@drawable/ic_landscape_onboarding_3_tablet"
+        app:srcCompat="@drawable/ic_landscape_onboarding_3_tablet"
         app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintDimensionRatio="40:39"
         app:layout_constraintStart_toStartOf="parent"
diff --git a/app/src/main/res/layout-sw600dp-land/profile_chooser_add_view.xml b/app/src/main/res/layout-sw600dp-land/profile_chooser_add_view.xml
index 5e34a5d1fc9..6339536d44e 100644
--- a/app/src/main/res/layout-sw600dp-land/profile_chooser_add_view.xml
+++ b/app/src/main/res/layout-sw600dp-land/profile_chooser_add_view.xml
@@ -39,7 +39,7 @@
         android:id="@+id/profile_add_button"
         android:layout_width="108dp"
         android:layout_height="108dp"
-        android:src="@drawable/ic_add_profile"
+        app:srcCompat="@{@drawable/ic_add_profile}"
         app:layoutMarginTop="@{hasProfileEverBeenAddedValue ? @dimen/profile_chooser_add_view_circular_image_margin_top_profile_already_added : @dimen/space_0dp}"
         app:civ_border_color="@color/avatarBorder"
         app:civ_border_width="1dp" />
diff --git a/app/src/main/res/layout-sw600dp-land/profile_chooser_fragment.xml b/app/src/main/res/layout-sw600dp-land/profile_chooser_fragment.xml
index e00baba31e8..7598fcc7260 100644
--- a/app/src/main/res/layout-sw600dp-land/profile_chooser_fragment.xml
+++ b/app/src/main/res/layout-sw600dp-land/profile_chooser_fragment.xml
@@ -37,7 +37,7 @@
           android:paddingStart="4dp"
           android:paddingTop="20dp"
           android:paddingEnd="20dp"
-          android:src="@drawable/ic_language_icon_grey_24dp"
+          app:srcCompat="@drawable/ic_language_icon_grey_24dp"
           android:visibility="gone"
           app:layout_constraintEnd_toEndOf="parent"
           app:layout_constraintTop_toTopOf="parent" />
@@ -121,7 +121,7 @@
         android:layout_height="48dp"
         android:layout_marginEnd="96dp"
         android:padding="8dp"
-        android:src="@drawable/ic_settings_grey_48dp" />
+        app:srcCompat="@drawable/ic_settings_grey_48dp" />
     </LinearLayout>
   </androidx.constraintlayout.widget.ConstraintLayout>
 </layout>
diff --git a/app/src/main/res/layout-sw600dp-land/profile_progress_header.xml b/app/src/main/res/layout-sw600dp-land/profile_progress_header.xml
index 9398bca7926..6848b0031ef 100644
--- a/app/src/main/res/layout-sw600dp-land/profile_progress_header.xml
+++ b/app/src/main/res/layout-sw600dp-land/profile_progress_header.xml
@@ -38,7 +38,7 @@
       android:onClick="@{() -> viewModel.clickOnProfilePicture()}"
       android:paddingStart="12dp"
       android:paddingTop="12dp"
-      android:src="@drawable/rounded_white_background_with_shadow"
+      app:srcCompat="@drawable/rounded_white_background_with_shadow"
       app:layout_constraintBottom_toBottomOf="@+id/profile_edit_image"
       app:layout_constraintEnd_toEndOf="@+id/profile_edit_image" />
 
diff --git a/app/src/main/res/layout-sw600dp-land/question_player_fragment.xml b/app/src/main/res/layout-sw600dp-land/question_player_fragment.xml
index 55251dd52f7..8f6b5818b8d 100644
--- a/app/src/main/res/layout-sw600dp-land/question_player_fragment.xml
+++ b/app/src/main/res/layout-sw600dp-land/question_player_fragment.xml
@@ -152,7 +152,7 @@
         android:layout_gravity="top|end"
         android:layout_margin="8dp"
         android:contentDescription="@string/new_hint_available"
-        android:src="@drawable/ic_dot_yellow_24dp"
+        app:srcCompat="@drawable/ic_dot_yellow_24dp"
         android:visibility="@{viewModel.isHintOpenedAndUnRevealed() ? View.VISIBLE : View.GONE}" />
 
       <ImageView
@@ -161,7 +161,7 @@
         android:layout_height="wrap_content"
         android:layout_margin="12dp"
         android:contentDescription="@string/show_hints_and_solution"
-        android:src="@drawable/ic_hint_bulb_white_24dp" />
+        app:srcCompat="@drawable/ic_hint_bulb_white_24dp" />
     </FrameLayout>
 
     <FrameLayout
diff --git a/app/src/main/res/layout-sw600dp-land/solution_summary.xml b/app/src/main/res/layout-sw600dp-land/solution_summary.xml
index 7abebb3ba6a..d75eccd4233 100644
--- a/app/src/main/res/layout-sw600dp-land/solution_summary.xml
+++ b/app/src/main/res/layout-sw600dp-land/solution_summary.xml
@@ -78,7 +78,7 @@
           android:layout_gravity="center_vertical"
           android:contentDescription="@string/show_hide_solution_list"
           android:padding="8dp"
-          android:src="@drawable/ic_arrow_drop_down_black_24dp"
+          app:srcCompat="@drawable/ic_arrow_drop_down_black_24dp"
           app:isRotationAnimationClockwise="@{isListExpanded}"
           app:rotationAnimationAngle="@{180f}" />
       </FrameLayout>
diff --git a/app/src/main/res/layout-sw600dp-land/topic_info_fragment.xml b/app/src/main/res/layout-sw600dp-land/topic_info_fragment.xml
index 428ddefc4f8..fb3a79937e2 100644
--- a/app/src/main/res/layout-sw600dp-land/topic_info_fragment.xml
+++ b/app/src/main/res/layout-sw600dp-land/topic_info_fragment.xml
@@ -99,7 +99,7 @@
           android:layout_height="20dp"
           android:layout_marginStart="64dp"
           android:layout_marginTop="32dp"
-          android:src="@{viewModel.downloadStatusIndicatorDrawableResourceId, default=@drawable/ic_available_offline_primary_24dp}"
+          app:srcCompat="@{viewModel.downloadStatusIndicatorDrawableResourceId, default=@drawable/ic_available_offline_primary_24dp}"
           app:layout_constraintBottom_toBottomOf="parent"
           app:layout_constraintStart_toStartOf="parent"
           app:layout_constraintTop_toBottomOf="@+id/see_more_text_view" />
diff --git a/app/src/main/res/layout-sw600dp-land/topic_lessons_story_summary.xml b/app/src/main/res/layout-sw600dp-land/topic_lessons_story_summary.xml
index c7b07e6e927..d3f338cd0e6 100644
--- a/app/src/main/res/layout-sw600dp-land/topic_lessons_story_summary.xml
+++ b/app/src/main/res/layout-sw600dp-land/topic_lessons_story_summary.xml
@@ -138,7 +138,7 @@
                 android:layout_height="wrap_content"
                 android:layout_gravity="center_horizontal|bottom"
                 android:contentDescription="@{isListExpanded ? @string/hide_chapter_list : @string/show_chapter_list}"
-                android:src="@drawable/ic_arrow_drop_down_black_24dp"
+                app:srcCompat="@drawable/ic_arrow_drop_down_black_24dp"
                 app:isRotationAnimationClockwise="@{isListExpanded}"
                 app:rotationAnimationAngle="@{180f}" />
             </FrameLayout>
diff --git a/app/src/main/res/layout-sw600dp-port/hints_summary.xml b/app/src/main/res/layout-sw600dp-port/hints_summary.xml
index 28dcfdd4ffb..c457db4d9ba 100644
--- a/app/src/main/res/layout-sw600dp-port/hints_summary.xml
+++ b/app/src/main/res/layout-sw600dp-port/hints_summary.xml
@@ -78,7 +78,7 @@
           android:layout_gravity="center_vertical"
           android:contentDescription="@{viewModel.computeHintListDropDownIconContentDescription()}"
           android:padding="8dp"
-          android:src="@drawable/ic_arrow_drop_down_black_24dp"
+          app:srcCompat="@drawable/ic_arrow_drop_down_black_24dp"
           app:isRotationAnimationClockwise="@{isListExpanded}"
           app:rotationAnimationAngle="@{180f}" />
       </FrameLayout>
diff --git a/app/src/main/res/layout-sw600dp-port/onboarding_fragment.xml b/app/src/main/res/layout-sw600dp-port/onboarding_fragment.xml
index 37cdf46fe28..7bfbe54ab2d 100644
--- a/app/src/main/res/layout-sw600dp-port/onboarding_fragment.xml
+++ b/app/src/main/res/layout-sw600dp-port/onboarding_fragment.xml
@@ -74,7 +74,7 @@
         android:minHeight="48dp"
         android:onClick="@{(v) -> presenter.clickOnNext()}"
         android:scaleType="center"
-        android:src="@drawable/ic_arrow_forward_black_24dp"
+        app:srcCompat="@drawable/ic_arrow_forward_black_24dp"
         android:visibility="@{viewModel.slideNumber != 3 ? View.VISIBLE: View.GONE, default=visible}"
         app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintEnd_toEndOf="parent"
diff --git a/app/src/main/res/layout-sw600dp-port/onboarding_slide.xml b/app/src/main/res/layout-sw600dp-port/onboarding_slide.xml
index 74a4ab27d9e..ef07a22d85b 100644
--- a/app/src/main/res/layout-sw600dp-port/onboarding_slide.xml
+++ b/app/src/main/res/layout-sw600dp-port/onboarding_slide.xml
@@ -27,7 +27,7 @@
         android:layout_width="0dp"
         android:layout_height="0dp"
         android:importantForAccessibility="no"
-        android:src="@{viewModel.slideImage}"
+        app:srcCompat="@{viewModel.slideImage}"
         app:layout_constraintDimensionRatio="5:4"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent"
diff --git a/app/src/main/res/layout-sw600dp-port/onboarding_slide_final.xml b/app/src/main/res/layout-sw600dp-port/onboarding_slide_final.xml
index 1890899d7cd..f7b1c43797a 100644
--- a/app/src/main/res/layout-sw600dp-port/onboarding_slide_final.xml
+++ b/app/src/main/res/layout-sw600dp-port/onboarding_slide_final.xml
@@ -28,7 +28,7 @@
         android:layout_width="0dp"
         android:layout_height="0dp"
         android:importantForAccessibility="no"
-        android:src="@drawable/ic_portrait_onboarding_3"
+        app:srcCompat="@drawable/ic_portrait_onboarding_3"
         app:layout_constraintDimensionRatio="5:4"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent"
diff --git a/app/src/main/res/layout-sw600dp-port/profile_chooser_add_view.xml b/app/src/main/res/layout-sw600dp-port/profile_chooser_add_view.xml
index 7ebf1309dd1..2b493e7cd69 100644
--- a/app/src/main/res/layout-sw600dp-port/profile_chooser_add_view.xml
+++ b/app/src/main/res/layout-sw600dp-port/profile_chooser_add_view.xml
@@ -40,7 +40,7 @@
         android:id="@+id/profile_add_button"
         android:layout_width="108dp"
         android:layout_height="108dp"
-        android:src="@drawable/ic_add_profile"
+        app:srcCompat="@{@drawable/ic_add_profile}"
         app:layoutMarginTop="@{hasProfileEverBeenAddedValue ? @dimen/profile_chooser_add_view_circular_image_margin_top_profile_already_added : @dimen/space_0dp}"
         app:civ_border_color="@color/avatarBorder"
         app:civ_border_width="1dp" />
diff --git a/app/src/main/res/layout-sw600dp-port/profile_chooser_fragment.xml b/app/src/main/res/layout-sw600dp-port/profile_chooser_fragment.xml
index 92c6e540cee..0c68b38ba4f 100644
--- a/app/src/main/res/layout-sw600dp-port/profile_chooser_fragment.xml
+++ b/app/src/main/res/layout-sw600dp-port/profile_chooser_fragment.xml
@@ -37,7 +37,7 @@
           android:paddingStart="4dp"
           android:paddingTop="20dp"
           android:paddingEnd="20dp"
-          android:src="@drawable/ic_language_icon_grey_24dp"
+          app:srcCompat="@drawable/ic_language_icon_grey_24dp"
           android:visibility="gone"
           app:layout_constraintEnd_toEndOf="parent"
           app:layout_constraintTop_toTopOf="parent" />
@@ -121,7 +121,7 @@
         android:layout_height="48dp"
         android:layout_marginEnd="64dp"
         android:padding="8dp"
-        android:src="@drawable/ic_settings_grey_48dp" />
+        app:srcCompat="@drawable/ic_settings_grey_48dp" />
     </LinearLayout>
   </androidx.constraintlayout.widget.ConstraintLayout>
 </layout>
diff --git a/app/src/main/res/layout-sw600dp-port/profile_progress_header.xml b/app/src/main/res/layout-sw600dp-port/profile_progress_header.xml
index 46455c87825..a7b3a4ce187 100644
--- a/app/src/main/res/layout-sw600dp-port/profile_progress_header.xml
+++ b/app/src/main/res/layout-sw600dp-port/profile_progress_header.xml
@@ -38,7 +38,7 @@
       android:onClick="@{() -> viewModel.clickOnProfilePicture()}"
       android:paddingStart="12dp"
       android:paddingTop="12dp"
-      android:src="@drawable/rounded_white_background_with_shadow"
+      app:srcCompat="@drawable/rounded_white_background_with_shadow"
       app:layout_constraintBottom_toBottomOf="@+id/profile_edit_image"
       app:layout_constraintEnd_toEndOf="@+id/profile_edit_image" />
 
diff --git a/app/src/main/res/layout-sw600dp-port/question_player_fragment.xml b/app/src/main/res/layout-sw600dp-port/question_player_fragment.xml
index ceaa478e9ab..ef3b272aceb 100644
--- a/app/src/main/res/layout-sw600dp-port/question_player_fragment.xml
+++ b/app/src/main/res/layout-sw600dp-port/question_player_fragment.xml
@@ -152,7 +152,7 @@
         android:layout_gravity="top|end"
         android:layout_margin="8dp"
         android:contentDescription="@string/new_hint_available"
-        android:src="@drawable/ic_dot_yellow_24dp"
+        app:srcCompat="@drawable/ic_dot_yellow_24dp"
         android:visibility="@{viewModel.isHintOpenedAndUnRevealed() ? View.VISIBLE : View.GONE}" />
 
       <ImageView
@@ -161,7 +161,7 @@
         android:layout_height="wrap_content"
         android:layout_margin="12dp"
         android:contentDescription="@string/show_hints_and_solution"
-        android:src="@drawable/ic_hint_bulb_white_24dp" />
+        app:srcCompat="@drawable/ic_hint_bulb_white_24dp" />
     </FrameLayout>
 
     <FrameLayout
diff --git a/app/src/main/res/layout-sw600dp-port/solution_summary.xml b/app/src/main/res/layout-sw600dp-port/solution_summary.xml
index 47233633595..7f705133636 100644
--- a/app/src/main/res/layout-sw600dp-port/solution_summary.xml
+++ b/app/src/main/res/layout-sw600dp-port/solution_summary.xml
@@ -78,7 +78,7 @@
           android:layout_gravity="center_vertical"
           android:contentDescription="@string/show_hide_solution_list"
           android:padding="8dp"
-          android:src="@drawable/ic_arrow_drop_down_black_24dp"
+          app:srcCompat="@drawable/ic_arrow_drop_down_black_24dp"
           app:isRotationAnimationClockwise="@{isListExpanded}"
           app:rotationAnimationAngle="@{180f}" />
       </FrameLayout>
diff --git a/app/src/main/res/layout-sw600dp-port/topic_info_fragment.xml b/app/src/main/res/layout-sw600dp-port/topic_info_fragment.xml
index 2aa1375f61a..c9bfa875c35 100644
--- a/app/src/main/res/layout-sw600dp-port/topic_info_fragment.xml
+++ b/app/src/main/res/layout-sw600dp-port/topic_info_fragment.xml
@@ -118,7 +118,7 @@
         android:layout_height="20dp"
         android:layout_marginStart="120dp"
         android:layout_marginTop="24dp"
-        android:src="@{viewModel.downloadStatusIndicatorDrawableResourceId, default=@drawable/ic_available_offline_primary_24dp}"
+        app:srcCompat="@{viewModel.downloadStatusIndicatorDrawableResourceId, default=@drawable/ic_available_offline_primary_24dp}"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toBottomOf="@+id/see_more_text_view" />
 
diff --git a/app/src/main/res/layout-sw600dp-port/topic_lessons_story_summary.xml b/app/src/main/res/layout-sw600dp-port/topic_lessons_story_summary.xml
index 25b801e8054..9649b299c79 100644
--- a/app/src/main/res/layout-sw600dp-port/topic_lessons_story_summary.xml
+++ b/app/src/main/res/layout-sw600dp-port/topic_lessons_story_summary.xml
@@ -138,7 +138,7 @@
                 android:layout_height="wrap_content"
                 android:layout_gravity="center_horizontal|bottom"
                 android:contentDescription="@{isListExpanded ? @string/hide_chapter_list : @string/show_chapter_list}"
-                android:src="@drawable/ic_arrow_drop_down_black_24dp"
+                app:srcCompat="@drawable/ic_arrow_drop_down_black_24dp"
                 app:isRotationAnimationClockwise="@{isListExpanded}"
                 app:rotationAnimationAngle="@{180f}" />
             </FrameLayout>
diff --git a/app/src/main/res/layout-sw600dp/help_activity.xml b/app/src/main/res/layout-sw600dp/help_activity.xml
index 219ff664632..1b812394dea 100644
--- a/app/src/main/res/layout-sw600dp/help_activity.xml
+++ b/app/src/main/res/layout-sw600dp/help_activity.xml
@@ -37,7 +37,7 @@
         android:background="@color/oppiaGreyBackground"
         android:contentDescription="@string/help_activity_back_arrow_description"
         android:padding="12dp"
-        android:src="@drawable/ic_arrow_back_black_24_dp"
+        app:srcCompat="@drawable/ic_arrow_back_black_24_dp"
         android:visibility="gone"
         app:layout_constraintStart_toEndOf="@id/multipane_guideline"
         app:layout_constraintTop_toTopOf="parent" />
diff --git a/app/src/main/res/layout-sw600dp/story_chapter_view.xml b/app/src/main/res/layout-sw600dp/story_chapter_view.xml
index 8ea5b6867a4..72b96f4a8ef 100644
--- a/app/src/main/res/layout-sw600dp/story_chapter_view.xml
+++ b/app/src/main/res/layout-sw600dp/story_chapter_view.xml
@@ -67,7 +67,7 @@
           android:layout_width="match_parent"
           android:layout_height="match_parent"
           android:scaleType="center"
-          android:src="@drawable/ic_baseline_lock_24"
+          app:srcCompat="@drawable/ic_baseline_lock_24"
           android:visibility="@{viewModel.chapterSummary.chapterPlayState == ChapterPlayState.NOT_PLAYABLE_MISSING_PREREQUISITES ? View.VISIBLE : View.INVISIBLE}"
           app:layout_constraintBottom_toBottomOf="@id/chapter_thumbnail"
           app:layout_constraintEnd_toEndOf="@id/chapter_thumbnail"
@@ -128,7 +128,7 @@
             android:layout_marginEnd="8dp"
             android:layout_marginBottom="4dp"
             android:contentDescription="@{@string/chapter_completed}"
-            android:src="@drawable/ic_check_24dp"
+            app:srcCompat="@drawable/ic_check_24dp"
             android:visibility="@{viewModel.chapterSummary.chapterPlayState == ChapterPlayState.COMPLETED ? View.VISIBLE : View.GONE}"
             app:layout_constraintBottom_toBottomOf="parent"
             app:layout_constraintEnd_toEndOf="parent"
diff --git a/app/src/main/res/layout/activity_view_binding_adapters_test.xml b/app/src/main/res/layout/activity_view_binding_adapters_test.xml
index ae933b4f361..1ea2f715569 100644
--- a/app/src/main/res/layout/activity_view_binding_adapters_test.xml
+++ b/app/src/main/res/layout/activity_view_binding_adapters_test.xml
@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<layout xmlns:android="http://schemas.android.com/apk/res/android">
+<layout xmlns:android="http://schemas.android.com/apk/res/android"
+  xmlns:app="http://schemas.android.com/apk/res-auto">
 
   <FrameLayout
     android:id="@+id/expand_list_icon"
@@ -15,6 +16,6 @@
       android:layout_height="48dp"
       android:layout_gravity="center_vertical"
       android:padding="8dp"
-      android:src="@drawable/ic_arrow_drop_down_black_24dp" />
+      app:srcCompat="@drawable/ic_arrow_drop_down_black_24dp" />
   </FrameLayout>
 </layout>
diff --git a/app/src/main/res/layout/add_profile_activity.xml b/app/src/main/res/layout/add_profile_activity.xml
index bf756349f13..3765a11afa0 100644
--- a/app/src/main/res/layout/add_profile_activity.xml
+++ b/app/src/main/res/layout/add_profile_activity.xml
@@ -45,7 +45,7 @@
             android:clickable="true"
             android:contentDescription="@string/current_profile_picture_content_description"
             android:focusable="true"
-            android:src="@drawable/ic_default_avatar"
+            app:srcCompat="@drawable/ic_default_avatar"
             app:add_shadow="true"
             app:layout_constraintEnd_toEndOf="parent"
             app:layout_constraintStart_toStartOf="parent"
@@ -59,7 +59,7 @@
             android:contentDescription="@string/edit_profile_picture_content_description"
             android:paddingStart="12dp"
             android:paddingTop="12dp"
-            android:src="@drawable/rounded_white_background_with_shadow"
+            app:srcCompat="@drawable/rounded_white_background_with_shadow"
             app:layout_constraintBottom_toBottomOf="@+id/add_profile_activity_user_image_view"
             app:layout_constraintEnd_toEndOf="@+id/add_profile_activity_user_image_view" />
 
@@ -113,7 +113,7 @@
             android:layout_height="48dp"
             android:contentDescription="@string/add_profile_info_content_description"
             android:padding="12dp"
-            android:src="@drawable/ic_info_icon"
+            app:srcCompat="@drawable/ic_info_icon"
             app:layout_constraintEnd_toEndOf="parent"
             app:layout_constraintTop_toTopOf="@+id/add_profile_activity_pin_check_box" />
 
diff --git a/app/src/main/res/layout/app_version_fragment.xml b/app/src/main/res/layout/app_version_fragment.xml
index 17c0b0ff013..3c0dae0e83e 100644
--- a/app/src/main/res/layout/app_version_fragment.xml
+++ b/app/src/main/res/layout/app_version_fragment.xml
@@ -36,7 +36,7 @@
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_marginStart="@dimen/app_version_image_view_margin_start"
-        android:src="@drawable/ic_info_icon_gray_24dp"
+        app:srcCompat="@drawable/ic_info_icon_gray_24dp"
         app:layout_constraintEnd_toStartOf="@id/app_last_update_date_text_view"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="@id/app_last_update_date_text_view" />
diff --git a/app/src/main/res/layout/audio_fragment.xml b/app/src/main/res/layout/audio_fragment.xml
index 6b7417560ab..63c5bbe3562 100755
--- a/app/src/main/res/layout/audio_fragment.xml
+++ b/app/src/main/res/layout/audio_fragment.xml
@@ -35,7 +35,7 @@
       android:contentDescription="@{viewModel.playStatusLiveData == UiAudioPlayStatus.PLAYING ? @string/audio_pause_description : @string/audio_play_description}"
       android:onClick="@{(v) -> viewModel.togglePlayPause(viewModel.playStatusLiveData)}"
       android:padding="12dp"
-      android:src="@{viewModel.playStatusLiveData == UiAudioPlayStatus.PLAYING ? @drawable/ic_pause_circle_filled_white_24dp : @drawable/ic_play_circle_filled_white_24dp}"
+      app:srcCompat="@{viewModel.playStatusLiveData == UiAudioPlayStatus.PLAYING ? @drawable/ic_pause_circle_filled_white_24dp : @drawable/ic_play_circle_filled_white_24dp}"
       app:layout_constraintBottom_toBottomOf="parent"
       app:layout_constraintStart_toStartOf="parent"
       app:layout_constraintTop_toTopOf="parent" />
@@ -69,7 +69,7 @@
       android:gravity="center"
       android:onClick="@{(v) -> audioFragment.languageSelectionClicked()}"
       android:padding="12dp"
-      android:src="@drawable/ic_audio_lang_24px"
+      app:srcCompat="@drawable/ic_audio_lang_24px"
       app:layout_constraintBottom_toBottomOf="parent"
       app:layout_constraintEnd_toEndOf="parent"
       app:layout_constraintTop_toTopOf="parent" />
diff --git a/app/src/main/res/layout/drag_drop_interaction_items.xml b/app/src/main/res/layout/drag_drop_interaction_items.xml
index 2c7a8a1dd3f..429c8799e47 100644
--- a/app/src/main/res/layout/drag_drop_interaction_items.xml
+++ b/app/src/main/res/layout/drag_drop_interaction_items.xml
@@ -45,7 +45,7 @@
           android:enabled="@{viewModel.itemIndex != 0}"
           android:focusable="true"
           android:onClick="@{(v) -> viewModel.handleUpMovement(adapter)}"
-          android:src="@drawable/ic_arrow_up_black_24dp"
+          app:srcCompat="@drawable/ic_arrow_up_black_24dp"
           android:tint="@{dragDropMoveUpItem.enabled? @color/mergeIconEnabled : @color/mergeIconDisabled}"
           app:layout_constraintBottom_toBottomOf="parent"
           app:layout_constraintEnd_toEndOf="parent"
@@ -62,7 +62,7 @@
           android:enabled="@{viewModel.itemIndex != viewModel.listSize-1}"
           android:focusable="true"
           android:onClick="@{(v) -> viewModel.handleDownMovement(adapter)}"
-          android:src="@drawable/ic_keyboard_arrow_down_black_24dp"
+          app:srcCompat="@drawable/ic_keyboard_arrow_down_black_24dp"
           android:tint="@{dragDropMoveDownItem.enabled? @color/mergeIconEnabled : @color/mergeIconDisabled}" />
       </LinearLayout>
 
@@ -91,7 +91,7 @@
       android:focusable="true"
       android:onClick="@{(v) -> viewModel.handleGrouping(adapter)}"
       android:padding="16dp"
-      android:src="@drawable/ic_merge_icon_24"
+      app:srcCompat="@drawable/ic_merge_icon_24"
       android:tint="@{dragDropContentGroupItem.enabled? @color/mergeIconEnabled : @color/mergeIconDisabled}"
       app:layout_constraintBottom_toBottomOf="parent"
       app:layout_constraintEnd_toEndOf="parent"
@@ -107,7 +107,7 @@
       android:focusable="true"
       android:onClick="@{(v) -> viewModel.handleUnlinking(adapter)}"
       android:padding="16dp"
-      android:src="@drawable/ic_unlink_icon_24"
+      app:srcCompat="@drawable/ic_unlink_icon_24"
       app:layout_constraintBottom_toTopOf="@+id/drag_drop_content_group_item"
       app:layout_constraintEnd_toEndOf="parent"
       app:layout_constraintTop_toTopOf="parent" />
diff --git a/app/src/main/res/layout/drawer_fragment.xml b/app/src/main/res/layout/drawer_fragment.xml
index b440a07d396..ae5fd677775 100644
--- a/app/src/main/res/layout/drawer_fragment.xml
+++ b/app/src/main/res/layout/drawer_fragment.xml
@@ -65,7 +65,7 @@
             android:layout_width="24dp"
             android:layout_height="24dp"
             android:layout_gravity="center_vertical"
-            android:src="@drawable/ic_baseline_code_24"
+            app:srcCompat="@drawable/ic_baseline_code_24"
             android:tint="@{footerViewModel.isDeveloperOptionsSelected ? @color/highlightedDeveloperOptionsNavMenuItem : @color/oppiaPrimaryTextDark}"/>
 
           <TextView
@@ -96,7 +96,7 @@
             android:layout_width="24dp"
             android:layout_height="24dp"
             android:layout_gravity="center_vertical"
-            android:src="@drawable/ic_admin_settings_icon_brown_24dp"
+            app:srcCompat="@drawable/ic_admin_settings_icon_brown_24dp"
             android:tint="@{footerViewModel.isAdministratorControlsSelected ? @color/highlightedNavMenuItem : @color/oppiaPrimaryTextDark}" />
 
           <TextView
diff --git a/app/src/main/res/layout/exploration_activity.xml b/app/src/main/res/layout/exploration_activity.xml
index aa7611596fa..482e5a75efa 100755
--- a/app/src/main/res/layout/exploration_activity.xml
+++ b/app/src/main/res/layout/exploration_activity.xml
@@ -65,7 +65,7 @@
             android:layout_gravity="end"
             android:contentDescription="@{viewModel.isAudioStreamingOn ? @string/audio_player_on : @string/audio_player_off}"
             android:scaleType="center"
-            android:src="@{viewModel.isAudioStreamingOn ? @drawable/ic_audio_streaming_on_24dp : @drawable/ic_audio_streaming_off_24dp}"
+            app:srcCompat="@{viewModel.isAudioStreamingOn ? @drawable/ic_audio_streaming_on_24dp : @drawable/ic_audio_streaming_off_24dp}"
             android:visibility="@{viewModel.showAudioButton ? View.VISIBLE : View.GONE}" />
         </LinearLayout>
       </androidx.appcompat.widget.Toolbar>
diff --git a/app/src/main/res/layout/force_network_type_network_item_view.xml b/app/src/main/res/layout/force_network_type_network_item_view.xml
index 86ecad0dac2..5c57171578a 100644
--- a/app/src/main/res/layout/force_network_type_network_item_view.xml
+++ b/app/src/main/res/layout/force_network_type_network_item_view.xml
@@ -42,7 +42,7 @@
       android:layout_marginEnd="18dp"
       android:layout_marginBottom="4dp"
       android:contentDescription="@{@string/force_network_type_network_selected}"
-      android:src="@drawable/ic_check_24dp"
+      app:srcCompat="@drawable/ic_check_24dp"
       android:visibility="@{isNetworkSelected ? View.VISIBLE : View.GONE }"
       app:layout_constraintBottom_toBottomOf="parent"
       app:layout_constraintEnd_toEndOf="parent"
diff --git a/app/src/main/res/layout/hints_summary.xml b/app/src/main/res/layout/hints_summary.xml
index 75db37f1e2b..7b0763ccce5 100644
--- a/app/src/main/res/layout/hints_summary.xml
+++ b/app/src/main/res/layout/hints_summary.xml
@@ -84,7 +84,7 @@
           android:layout_gravity="center_vertical"
           android:contentDescription="@{viewModel.computeHintListDropDownIconContentDescription()}"
           android:padding="8dp"
-          android:src="@drawable/ic_arrow_drop_down_black_24dp"
+          app:srcCompat="@drawable/ic_arrow_drop_down_black_24dp"
           app:isRotationAnimationClockwise="@{isListExpanded}"
           app:rotationAnimationAngle="@{180f}" />
       </FrameLayout>
diff --git a/app/src/main/res/layout/image_region_selection_test_fragment.xml b/app/src/main/res/layout/image_region_selection_test_fragment.xml
index 57758ce4d1d..5ff07314181 100644
--- a/app/src/main/res/layout/image_region_selection_test_fragment.xml
+++ b/app/src/main/res/layout/image_region_selection_test_fragment.xml
@@ -1,6 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:tools="http://schemas.android.com/tools"
+  xmlns:app="http://schemas.android.com/apk/res-auto"
   android:id="@+id/image_parent_view"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
@@ -11,7 +12,7 @@
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:adjustViewBounds="true"
-    android:src="@drawable/testing_fraction" />
+    app:srcCompat="@drawable/testing_fraction" />
 
   <View
     android:id="@+id/default_selected_region"
diff --git a/app/src/main/res/layout/lessons_chapter_view.xml b/app/src/main/res/layout/lessons_chapter_view.xml
index 3b7897fb411..d3fdbbca226 100644
--- a/app/src/main/res/layout/lessons_chapter_view.xml
+++ b/app/src/main/res/layout/lessons_chapter_view.xml
@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<layout xmlns:android="http://schemas.android.com/apk/res/android">
+<layout xmlns:android="http://schemas.android.com/apk/res/android"
+  xmlns:app="http://schemas.android.com/apk/res-auto">
 
   <data>
 
@@ -31,7 +32,7 @@
       android:layout_marginStart="16dp"
       android:layout_marginEnd="8dp"
       android:contentDescription="@{viewModel.computeChapterPlayStateIconContentDescription()}"
-      android:src="@{viewModel.chapterPlayState == ChapterPlayState.COMPLETED?@drawable/ic_check_24dp:@drawable/ic_pending_24dp}"
+      app:srcCompat="@{viewModel.chapterPlayState == ChapterPlayState.COMPLETED?@drawable/ic_check_24dp:@drawable/ic_pending_24dp}"
       android:visibility="@{(viewModel.chapterPlayState == ChapterPlayState.COMPLETED || viewModel.chapterPlayState == ChapterPlayState.IN_PROGRESS_SAVED)?View.VISIBLE : View.INVISIBLE}" />
 
     <TextView
diff --git a/app/src/main/res/layout/mark_chapters_completed_chapter_summary_view.xml b/app/src/main/res/layout/mark_chapters_completed_chapter_summary_view.xml
index 6456253c206..ba8f508c13a 100644
--- a/app/src/main/res/layout/mark_chapters_completed_chapter_summary_view.xml
+++ b/app/src/main/res/layout/mark_chapters_completed_chapter_summary_view.xml
@@ -28,7 +28,7 @@
       android:layout_height="wrap_content"
       android:button="@drawable/selector_checkbox"
       android:checked="@{isChapterChecked}"
-      android:drawableStart="@android:color/transparent"
+      app:drawableStartCompat="@android:color/transparent"
       android:drawablePadding="20dp"
       android:enabled="@{isChapterCheckboxEnabled}"
       android:fontFamily="sans-serif"
diff --git a/app/src/main/res/layout/mark_stories_completed_story_summary_view.xml b/app/src/main/res/layout/mark_stories_completed_story_summary_view.xml
index e08520fdec0..938a6f4c55a 100644
--- a/app/src/main/res/layout/mark_stories_completed_story_summary_view.xml
+++ b/app/src/main/res/layout/mark_stories_completed_story_summary_view.xml
@@ -24,7 +24,7 @@
       android:layout_height="wrap_content"
       android:button="@drawable/selector_checkbox"
       android:checked="@{isStoryChecked}"
-      android:drawableStart="@android:color/transparent"
+      app:drawableStartCompat="@android:color/transparent"
       android:drawablePadding="20dp"
       android:fontFamily="sans-serif"
       android:gravity="start|top"
diff --git a/app/src/main/res/layout/mark_topics_completed_topic_view.xml b/app/src/main/res/layout/mark_topics_completed_topic_view.xml
index ddf0a94862e..349cd57644e 100644
--- a/app/src/main/res/layout/mark_topics_completed_topic_view.xml
+++ b/app/src/main/res/layout/mark_topics_completed_topic_view.xml
@@ -24,7 +24,7 @@
       android:layout_height="wrap_content"
       android:button="@drawable/selector_checkbox"
       android:checked="@{isTopicChecked}"
-      android:drawableStart="@android:color/transparent"
+      app:drawableStartCompat="@android:color/transparent"
       android:drawablePadding="20dp"
       android:fontFamily="sans-serif"
       android:gravity="start|top"
diff --git a/app/src/main/res/layout/onboarding_fragment.xml b/app/src/main/res/layout/onboarding_fragment.xml
index 6995674045b..4af56ab2a6f 100644
--- a/app/src/main/res/layout/onboarding_fragment.xml
+++ b/app/src/main/res/layout/onboarding_fragment.xml
@@ -74,7 +74,7 @@
         android:onClick="@{(v) -> presenter.clickOnNext()}"
         android:paddingStart="12dp"
         android:paddingEnd="12dp"
-        android:src="@drawable/ic_arrow_forward_black_24dp"
+        app:srcCompat="@drawable/ic_arrow_forward_black_24dp"
         android:visibility="@{viewModel.slideNumber != 3 ? View.VISIBLE: View.GONE, default=visible}"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintTop_toTopOf="@+id/slide_dots_container" />
diff --git a/app/src/main/res/layout/onboarding_slide.xml b/app/src/main/res/layout/onboarding_slide.xml
index 72ac87b4bff..b3b42071e30 100644
--- a/app/src/main/res/layout/onboarding_slide.xml
+++ b/app/src/main/res/layout/onboarding_slide.xml
@@ -27,7 +27,7 @@
         android:layout_width="0dp"
         android:layout_height="0dp"
         android:importantForAccessibility="no"
-        android:src="@{viewModel.slideImage}"
+        app:srcCompat="@{viewModel.slideImage}"
         app:layout_constraintDimensionRatio="5:4"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent"
diff --git a/app/src/main/res/layout/onboarding_slide_final.xml b/app/src/main/res/layout/onboarding_slide_final.xml
index 40158512bd7..b9d63d9d3c3 100644
--- a/app/src/main/res/layout/onboarding_slide_final.xml
+++ b/app/src/main/res/layout/onboarding_slide_final.xml
@@ -29,7 +29,7 @@
         android:layout_width="0dp"
         android:layout_height="0dp"
         android:importantForAccessibility="no"
-        android:src="@drawable/ic_portrait_onboarding_3"
+        app:srcCompat="@drawable/ic_portrait_onboarding_3"
         app:layout_constraintDimensionRatio="5:4"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent"
diff --git a/app/src/main/res/layout/pin_password_activity.xml b/app/src/main/res/layout/pin_password_activity.xml
index d45770e047a..59065c76ec2 100644
--- a/app/src/main/res/layout/pin_password_activity.xml
+++ b/app/src/main/res/layout/pin_password_activity.xml
@@ -173,7 +173,7 @@
               android:layout_height="32dp"
               android:layout_gravity="center_horizontal"
               android:contentDescription="@{viewModel.showPassword ? @string/password_shown_icon : @string/password_hidden_icon}"
-              android:src="@{viewModel.showPassword ? @drawable/ic_show_eye_icon : @drawable/ic_hide_eye_icon}" />
+              app:srcCompat="@{viewModel.showPassword ? @drawable/ic_show_eye_icon : @drawable/ic_hide_eye_icon}" />
 
             <TextView
               android:id="@+id/show_hide_password_text_view"
diff --git a/app/src/main/res/layout/previous_responses_header_item.xml b/app/src/main/res/layout/previous_responses_header_item.xml
index dc52713c12f..099e9ddc247 100644
--- a/app/src/main/res/layout/previous_responses_header_item.xml
+++ b/app/src/main/res/layout/previous_responses_header_item.xml
@@ -52,7 +52,7 @@
       android:id="@+id/previous_responses_header_text"
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
-      android:drawableEnd="@{viewModel.isExpanded ? @drawable/ic_arrow_down_grey_24dp : @drawable/ic_arrow_right_grey_24dp}"
+      app:drawableEndCompat="@{viewModel.isExpanded ? @drawable/ic_arrow_down_grey_24dp : @drawable/ic_arrow_right_grey_24dp}"
       android:fontFamily="sans-serif-medium"
       android:gravity="center_vertical"
       android:paddingStart="8dp"
diff --git a/app/src/main/res/layout/profile_chooser_add_view.xml b/app/src/main/res/layout/profile_chooser_add_view.xml
index 25f4a55ee85..48ba75cff99 100644
--- a/app/src/main/res/layout/profile_chooser_add_view.xml
+++ b/app/src/main/res/layout/profile_chooser_add_view.xml
@@ -35,7 +35,7 @@
         android:id="@+id/profile_add_button"
         android:layout_width="72dp"
         android:layout_height="72dp"
-        android:src="@drawable/ic_add_profile"
+        app:srcCompat="@{@drawable/ic_add_profile}"
         app:civ_border_color="@color/avatarBorder"
         app:civ_border_width="1dp" />
 
diff --git a/app/src/main/res/layout/profile_chooser_fragment.xml b/app/src/main/res/layout/profile_chooser_fragment.xml
index bba2aeb6c10..cb7210cc957 100644
--- a/app/src/main/res/layout/profile_chooser_fragment.xml
+++ b/app/src/main/res/layout/profile_chooser_fragment.xml
@@ -33,7 +33,7 @@
           android:paddingStart="4dp"
           android:paddingTop="20dp"
           android:paddingEnd="20dp"
-          android:src="@drawable/ic_language_icon_grey_24dp"
+          app:srcCompat="@drawable/ic_language_icon_grey_24dp"
           android:visibility="gone"
           app:layout_constraintEnd_toEndOf="parent"
           app:layout_constraintTop_toTopOf="parent"/>
@@ -117,7 +117,7 @@
         android:paddingTop="12dp"
         android:paddingEnd="16dp"
         android:paddingBottom="12dp"
-        android:src="@drawable/ic_settings_grey_48dp" />
+        app:srcCompat="@drawable/ic_settings_grey_48dp" />
     </LinearLayout>
   </androidx.constraintlayout.widget.ConstraintLayout>
 </layout>
diff --git a/app/src/main/res/layout/profile_progress_header.xml b/app/src/main/res/layout/profile_progress_header.xml
index 706fe2ecc61..c83060e0fd7 100644
--- a/app/src/main/res/layout/profile_progress_header.xml
+++ b/app/src/main/res/layout/profile_progress_header.xml
@@ -40,7 +40,7 @@
       android:onClick="@{() -> viewModel.clickOnProfilePicture()}"
       android:paddingStart="8dp"
       android:paddingTop="8dp"
-      android:src="@drawable/rounded_white_background_with_shadow"
+      app:srcCompat="@drawable/rounded_white_background_with_shadow"
       app:layout_constraintBottom_toBottomOf="@+id/profile_edit_image"
       app:layout_constraintEnd_toEndOf="@+id/profile_edit_image"/>
 
diff --git a/app/src/main/res/layout/question_player_fragment.xml b/app/src/main/res/layout/question_player_fragment.xml
index f0d1fc08d77..7591436349e 100644
--- a/app/src/main/res/layout/question_player_fragment.xml
+++ b/app/src/main/res/layout/question_player_fragment.xml
@@ -128,7 +128,7 @@
           android:layout_gravity="top|end"
           android:layout_margin="8dp"
           android:contentDescription="@string/new_hint_available"
-          android:src="@drawable/ic_dot_yellow_24dp"
+          app:srcCompat="@drawable/ic_dot_yellow_24dp"
           android:visibility="@{viewModel.isHintOpenedAndUnRevealed() ? View.VISIBLE : View.GONE}" />
 
         <ImageView
@@ -137,7 +137,7 @@
           android:layout_height="wrap_content"
           android:layout_margin="12dp"
           android:contentDescription="@string/show_hints_and_solution"
-          android:src="@drawable/ic_hint_bulb_white_24dp" />
+          app:srcCompat="@drawable/ic_hint_bulb_white_24dp" />
       </FrameLayout>
 
       <TextView
diff --git a/app/src/main/res/layout/replay_button_item.xml b/app/src/main/res/layout/replay_button_item.xml
index 33f1f6a8fb5..83ac66ed6b7 100644
--- a/app/src/main/res/layout/replay_button_item.xml
+++ b/app/src/main/res/layout/replay_button_item.xml
@@ -21,7 +21,7 @@
       android:id="@+id/replay_button"
       style="@style/StateButtonActive"
       android:background="@drawable/state_button_orange_background"
-      android:drawableStart="@drawable/ic_refresh_white_24dp"
+      app:drawableStartCompat="@drawable/ic_refresh_white_24dp"
       android:drawablePadding="4dp"
       android:onClick="@{(v) -> buttonViewModel.replayButtonListener.onReplayButtonClicked()}"
       android:paddingStart="24dp"
diff --git a/app/src/main/res/layout/solution_summary.xml b/app/src/main/res/layout/solution_summary.xml
index f609ded534c..60db757ac39 100644
--- a/app/src/main/res/layout/solution_summary.xml
+++ b/app/src/main/res/layout/solution_summary.xml
@@ -87,7 +87,7 @@
           android:padding="8dp"
           android:layout_gravity="center_vertical"
           android:contentDescription="@string/show_hide_solution_list"
-          android:src="@drawable/ic_arrow_drop_down_black_24dp"
+          app:srcCompat="@drawable/ic_arrow_drop_down_black_24dp"
           app:isRotationAnimationClockwise="@{isListExpanded}"
           app:rotationAnimationAngle="@{180f}" />
       </FrameLayout>
diff --git a/app/src/main/res/layout/state_fragment.xml b/app/src/main/res/layout/state_fragment.xml
index 3568b2df265..c70dd2cbc7c 100755
--- a/app/src/main/res/layout/state_fragment.xml
+++ b/app/src/main/res/layout/state_fragment.xml
@@ -114,7 +114,7 @@
         android:layout_gravity="top|end"
         android:layout_margin="8dp"
         android:contentDescription="@string/new_hint_available"
-        android:src="@drawable/ic_dot_yellow_24dp"
+        app:srcCompat="@drawable/ic_dot_yellow_24dp"
         android:visibility="@{viewModel.isHintOpenedAndUnRevealed() ? View.VISIBLE : View.GONE}" />
 
       <ImageView
@@ -123,7 +123,7 @@
         android:layout_height="wrap_content"
         android:layout_margin="12dp"
         android:contentDescription="@string/show_hints_and_solution"
-        android:src="@drawable/ic_hint_bulb_white_24dp" />
+        app:srcCompat="@drawable/ic_hint_bulb_white_24dp" />
     </FrameLayout>
 
     <FrameLayout
diff --git a/app/src/main/res/layout/story_chapter_view.xml b/app/src/main/res/layout/story_chapter_view.xml
index 8ea5b6867a4..72b96f4a8ef 100644
--- a/app/src/main/res/layout/story_chapter_view.xml
+++ b/app/src/main/res/layout/story_chapter_view.xml
@@ -67,7 +67,7 @@
           android:layout_width="match_parent"
           android:layout_height="match_parent"
           android:scaleType="center"
-          android:src="@drawable/ic_baseline_lock_24"
+          app:srcCompat="@drawable/ic_baseline_lock_24"
           android:visibility="@{viewModel.chapterSummary.chapterPlayState == ChapterPlayState.NOT_PLAYABLE_MISSING_PREREQUISITES ? View.VISIBLE : View.INVISIBLE}"
           app:layout_constraintBottom_toBottomOf="@id/chapter_thumbnail"
           app:layout_constraintEnd_toEndOf="@id/chapter_thumbnail"
@@ -128,7 +128,7 @@
             android:layout_marginEnd="8dp"
             android:layout_marginBottom="4dp"
             android:contentDescription="@{@string/chapter_completed}"
-            android:src="@drawable/ic_check_24dp"
+            app:srcCompat="@drawable/ic_check_24dp"
             android:visibility="@{viewModel.chapterSummary.chapterPlayState == ChapterPlayState.COMPLETED ? View.VISIBLE : View.GONE}"
             app:layout_constraintBottom_toBottomOf="parent"
             app:layout_constraintEnd_toEndOf="parent"
diff --git a/app/src/main/res/layout/submitted_answer_item.xml b/app/src/main/res/layout/submitted_answer_item.xml
index 935dc0c97d4..eeaa19c53b0 100644
--- a/app/src/main/res/layout/submitted_answer_item.xml
+++ b/app/src/main/res/layout/submitted_answer_item.xml
@@ -88,7 +88,7 @@
       android:layout_gravity="center_vertical"
       android:layout_marginStart="@dimen/answer_tick_margin"
       android:importantForAccessibility="no"
-      android:src="@drawable/ic_check_primary"
+      app:srcCompat="@drawable/ic_check_primary"
       android:visibility="@{viewModel.isCorrectAnswer &amp;&amp; !viewModel.hasConversationView ? View.VISIBLE : View.GONE}"
       app:layout_constraintBottom_toBottomOf="parent"
       app:layout_constraintStart_toEndOf="@+id/submitted_answer_text_view"
diff --git a/app/src/main/res/layout/topic_info_fragment.xml b/app/src/main/res/layout/topic_info_fragment.xml
index b8ba29b610b..9b93ba58a2a 100644
--- a/app/src/main/res/layout/topic_info_fragment.xml
+++ b/app/src/main/res/layout/topic_info_fragment.xml
@@ -125,7 +125,7 @@
         android:layout_marginStart="32dp"
         android:layout_marginTop="24dp"
         android:layout_marginBottom="32dp"
-        android:src="@{viewModel.downloadStatusIndicatorDrawableResourceId, default=@drawable/ic_available_offline_primary_24dp}"
+        app:srcCompat="@{viewModel.downloadStatusIndicatorDrawableResourceId, default=@drawable/ic_available_offline_primary_24dp}"
         app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toBottomOf="@+id/see_more_text_view" />
diff --git a/app/src/main/res/layout/topic_lessons_story_summary.xml b/app/src/main/res/layout/topic_lessons_story_summary.xml
index 722c8bb94f6..9e37a313bf3 100644
--- a/app/src/main/res/layout/topic_lessons_story_summary.xml
+++ b/app/src/main/res/layout/topic_lessons_story_summary.xml
@@ -135,7 +135,7 @@
               android:layout_height="wrap_content"
               android:layout_gravity="center_horizontal|bottom"
               android:contentDescription="@{isListExpanded ? @string/hide_chapter_list : @string/show_chapter_list}"
-              android:src="@drawable/ic_arrow_drop_down_black_24dp"
+              app:srcCompat="@drawable/ic_arrow_drop_down_black_24dp"
               app:isRotationAnimationClockwise="@{isListExpanded}"
               app:rotationAnimationAngle="@{180f}" />
           </FrameLayout>
diff --git a/app/src/main/res/layout/topic_practice_subtopic.xml b/app/src/main/res/layout/topic_practice_subtopic.xml
index d476aef4138..d08d11b5a40 100755
--- a/app/src/main/res/layout/topic_practice_subtopic.xml
+++ b/app/src/main/res/layout/topic_practice_subtopic.xml
@@ -45,7 +45,7 @@
           android:layout_height="wrap_content"
           android:button="@drawable/selector_checkbox"
           android:checked="@{isChecked}"
-          android:drawableStart="@android:color/transparent"
+          app:drawableStartCompat="@android:color/transparent"
           android:drawablePadding="20dp"
           android:fontFamily="sans-serif"
           android:gravity="start|top"
diff --git a/app/src/main/res/layout/walkthrough_activity.xml b/app/src/main/res/layout/walkthrough_activity.xml
index 114fd74982c..d4c26c4a22f 100644
--- a/app/src/main/res/layout/walkthrough_activity.xml
+++ b/app/src/main/res/layout/walkthrough_activity.xml
@@ -37,7 +37,7 @@
       android:contentDescription="@string/back_button"
       android:focusable="true"
       android:onClick="@{(v) -> presenter.moveToPreviousPage(viewModel.currentProgress)}"
-      android:src="@drawable/ic_arrow_back_white_24dp"
+      app:srcCompat="@drawable/ic_arrow_back_white_24dp"
       android:tint="@color/grey"
       app:layout_constraintStart_toStartOf="parent"
       app:layout_constraintTop_toTopOf="parent" />
diff --git a/app/src/main/res/layout/walkthrough_final_fragment.xml b/app/src/main/res/layout/walkthrough_final_fragment.xml
index 75d1ef649a9..6bcc514b99a 100644
--- a/app/src/main/res/layout/walkthrough_final_fragment.xml
+++ b/app/src/main/res/layout/walkthrough_final_fragment.xml
@@ -27,7 +27,7 @@
         android:layout_width="180dp"
         android:layout_height="180dp"
         android:layout_marginTop="32dp"
-        android:src="@drawable/ic_portrait_onboarding_0"
+        app:srcCompat="@drawable/ic_portrait_onboarding_0"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toBottomOf="@+id/walkthrough_final_title_text_view" />
diff --git a/app/src/main/res/layout/walkthrough_welcome_fragment.xml b/app/src/main/res/layout/walkthrough_welcome_fragment.xml
index 002c9d57959..8f915dd3f0f 100644
--- a/app/src/main/res/layout/walkthrough_welcome_fragment.xml
+++ b/app/src/main/res/layout/walkthrough_welcome_fragment.xml
@@ -58,7 +58,7 @@
         android:layout_width="180dp"
         android:layout_height="180dp"
         android:layout_marginTop="32dp"
-        android:src="@drawable/ic_portrait_onboarding_0"
+        app:srcCompat="@drawable/ic_portrait_onboarding_0"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toBottomOf="@+id/walkthrough_welcome_description_text_view" />
diff --git a/app/src/main/res/values/styles.xml b/app/src/main/res/values/styles.xml
index 6b271c3c3a9..16a1d20e97a 100644
--- a/app/src/main/res/values/styles.xml
+++ b/app/src/main/res/values/styles.xml
@@ -88,7 +88,7 @@
     <item name="android:background">@drawable/previous_next_state_image_view_background</item>
     <item name="android:contentDescription">@string/previous_state_description</item>
     <item name="android:padding">12dp</item>
-    <item name="android:src">@drawable/ic_arrow_back_oppia_dark_blue_24dp</item>
+    <item name="srcCompat">@drawable/ic_arrow_back_oppia_dark_blue_24dp</item>
   </style>
   <!-- NEXT BUTTON STYLE -->
   <style name="NextButton" parent="TextAppearance.AppCompat.Widget.Button">
@@ -101,7 +101,7 @@
     <item name="android:background">@drawable/previous_next_state_image_view_background</item>
     <item name="android:contentDescription">@string/next_state_description</item>
     <item name="android:padding">12dp</item>
-    <item name="android:src">@drawable/ic_arrow_forward_oppia_dark_blue_24dp</item>
+    <item name="srcCompat">@drawable/ic_arrow_forward_oppia_dark_blue_24dp</item>
   </style>
 
   <style name="TabLayout" parent="Widget.Design.TabLayout">
@@ -297,7 +297,7 @@
     <item name="android:paddingStart">12dp</item>
     <item name="android:background">@drawable/start_over_button_background</item>
     <item name="android:fontFamily">sans-serif-medium</item>
-    <item name="android:drawableStart">@drawable/ic_start_over_24dp</item>
+    <item name="drawableStartCompat">@drawable/ic_start_over_24dp</item>
     <item name="android:drawablePadding">4dp</item>
     <item name="drawableTint">@color/oppiaPrimaryDark</item>
     <item name="android:textAllCaps">true</item>
@@ -312,7 +312,7 @@
     <item name="android:paddingEnd">12dp</item>
     <item name="android:paddingStart">12dp</item>
     <item name="android:background">@drawable/state_button_primary_background</item>
-    <item name="android:drawableEnd">@drawable/ic_arrow_right_alt_24dp</item>
+    <item name="drawableEndCompat">@drawable/ic_arrow_right_alt_24dp</item>
     <item name="drawableTint">@color/white</item>
     <item name="android:fontFamily">sans-serif-medium</item>
     <item name="android:minHeight">@dimen/clickable_item_min_height</item>
diff --git a/app/src/test/java/org/oppia/android/app/testing/PlatformParameterIntegrationTest.kt b/app/src/test/java/org/oppia/android/app/testing/PlatformParameterIntegrationTest.kt
index 2ddedc4de4b..73932a62756 100644
--- a/app/src/test/java/org/oppia/android/app/testing/PlatformParameterIntegrationTest.kt
+++ b/app/src/test/java/org/oppia/android/app/testing/PlatformParameterIntegrationTest.kt
@@ -15,6 +15,7 @@ import androidx.work.WorkInfo
 import androidx.work.WorkManager
 import androidx.work.impl.utils.SynchronousExecutor
 import androidx.work.testing.WorkManagerTestInitHelper
+import com.google.common.base.Optional
 import com.google.common.truth.Truth.assertThat
 import dagger.Component
 import dagger.Module
@@ -298,17 +299,19 @@ class PlatformParameterIntegrationTest {
       jsonPrefixNetworkInterceptor: JsonPrefixNetworkInterceptor,
       remoteAuthNetworkInterceptor: RemoteAuthNetworkInterceptor,
       @BaseUrl baseUrl: String
-    ): Retrofit {
+    ): Optional<Retrofit> {
       val client = OkHttpClient.Builder()
         .addInterceptor(jsonPrefixNetworkInterceptor)
         .addInterceptor(remoteAuthNetworkInterceptor)
         .build()
 
-      return Retrofit.Builder()
-        .baseUrl(baseUrl)
-        .addConverterFactory(MoshiConverterFactory.create())
-        .client(client)
-        .build()
+      return Optional.of(
+        Retrofit.Builder()
+          .baseUrl(baseUrl)
+          .addConverterFactory(MoshiConverterFactory.create())
+          .client(client)
+          .build()
+      )
     }
 
     @Provides
@@ -316,9 +319,11 @@ class PlatformParameterIntegrationTest {
     fun provideNetworkApiKey(): String = ""
 
     @Provides
-    fun provideMockPlatformParameterService(mockRetrofit: MockRetrofit): PlatformParameterService {
+    fun provideMockPlatformParameterService(
+      mockRetrofit: MockRetrofit
+    ): Optional<PlatformParameterService> {
       val delegate = mockRetrofit.create(PlatformParameterService::class.java)
-      return MockPlatformParameterService(delegate)
+      return Optional.of(MockPlatformParameterService(delegate))
     }
   }
 
diff --git a/build_flavors.bzl b/build_flavors.bzl
index f4260b0eadd..e026c9c4e4b 100644
--- a/build_flavors.bzl
+++ b/build_flavors.bzl
@@ -3,53 +3,91 @@ Macros & definitions corresponding to Oppia binary build flavors.
 """
 
 load("//:oppia_android_application.bzl", "declare_deployable_application", "oppia_android_application")
-load("//:version.bzl", "MAJOR_VERSION", "MINOR_VERSION", "VERSION_CODE")
+load("//:version.bzl", "MAJOR_VERSION", "MINOR_VERSION", "OPPIA_ALPHA_KITKAT_VERSION_CODE", "OPPIA_ALPHA_VERSION_CODE", "OPPIA_DEV_KITKAT_VERSION_CODE", "OPPIA_DEV_VERSION_CODE")
 
 # Defines the list of flavors available to build the Oppia app in. Note to developers: this list
 # should be ordered by the development pipeline (i.e. features go through dev first, then other
 # flavors as they mature).
 AVAILABLE_FLAVORS = [
     "dev",
+    "dev_kitkat",
     "alpha",
+    "alpha_kitkat",
+]
+
+# This file contains the list of classes that must be in the main dex list for the legacy multidex
+# build used on KitKat devices. Generally, this is the main application class is needed so that it
+# can load multidex support, plus any dependencies needed by that pipeline.
+_MAIN_DEX_LIST_TARGET_KITKAT = "//:config/kitkat_main_dex_class_list.txt"
+
+# keep sorted
+_PRODUCTION_PROGUARD_SPECS = [
+    "config/proguard/android-proguard-rules.pro",
+    "config/proguard/androidx-proguard-rules.pro",
+    "config/proguard/firebase-components-proguard-rules.pro",
+    "config/proguard/glide-proguard-rules.pro",
+    "config/proguard/google-play-services-proguard-rules.pro",
+    "config/proguard/guava-proguard-rules.pro",
+    "config/proguard/kotlin-proguard-rules.pro",
+    "config/proguard/kotlinpoet-javapoet-proguard-rules.pro",
+    "config/proguard/material-proguard-rules.pro",
+    "config/proguard/moshi-proguard-rules.pro",
+    "config/proguard/okhttp-proguard-rules.pro",
+    "config/proguard/oppia-prod-proguard-rules.pro",
+    "config/proguard/protobuf-proguard-rules.pro",
 ]
 
 # Note to developers: keys of this dict should follow the order of AVAILABLE_FLAVORS.
 _FLAVOR_METADATA = {
     "dev": {
+        "manifest": "//app:src/main/AndroidManifest.xml",
+        "min_sdk_version": 21,
+        "target_sdk_version": 29,
+        "multidex": "native",
+        "proguard_specs": [],  # Developer builds are not optimized.
+        "production_release": False,
+        "deps": [
+            "//app",
+        ],
+        "version_code": OPPIA_DEV_VERSION_CODE,
+    },
+    "dev_kitkat": {
         "manifest": "//app:src/main/AndroidManifest.xml",
         "min_sdk_version": 19,
         "target_sdk_version": 29,
-        "multidex": "native",  # Legacy multidex not needed for dev builds.
+        "multidex": "manual_main_dex",
+        "main_dex_list": _MAIN_DEX_LIST_TARGET_KITKAT,
         "proguard_specs": [],  # Developer builds are not optimized.
         "production_release": False,
         "deps": [
             "//app",
         ],
+        "version_code": OPPIA_DEV_KITKAT_VERSION_CODE,
     },
     "alpha": {
         "manifest": "//app:src/main/AndroidManifest.xml",
-        "min_sdk_version": 19,
+        "min_sdk_version": 21,
         "target_sdk_version": 29,
-        "multidex": "legacy",
-        "proguard_specs": [
-            "config/proguard/android-proguard-rules.pro",
-            "config/proguard/androidx-proguard-rules.pro",
-            "config/proguard/firebase-components-proguard-rules.pro",
-            "config/proguard/glide-proguard-rules.pro",
-            "config/proguard/google-play-services-proguard-rules.pro",
-            "config/proguard/guava-proguard-rules.pro",
-            "config/proguard/kotlin-proguard-rules.pro",
-            "config/proguard/kotlinpoet-javapoet-proguard-rules.pro",
-            "config/proguard/material-proguard-rules.pro",
-            "config/proguard/moshi-proguard-rules.pro",
-            "config/proguard/okhttp-proguard-rules.pro",
-            "config/proguard/oppia-prod-proguard-rules.pro",
-            "config/proguard/protobuf-proguard-rules.pro",
+        "multidex": "native",
+        "proguard_specs": _PRODUCTION_PROGUARD_SPECS,
+        "production_release": True,
+        "deps": [
+            "//app",
         ],
+        "version_code": OPPIA_ALPHA_VERSION_CODE,
+    },
+    "alpha_kitkat": {
+        "manifest": "//app:src/main/AndroidManifest.xml",
+        "min_sdk_version": 19,
+        "target_sdk_version": 29,
+        "multidex": "manual_main_dex",
+        "main_dex_list": _MAIN_DEX_LIST_TARGET_KITKAT,
+        "proguard_specs": [],  # TODO(#3886): Re-add Proguard support to alpha_kitkat.
         "production_release": True,
         "deps": [
             "//app",
         ],
+        "version_code": OPPIA_ALPHA_KITKAT_VERSION_CODE,
     },
 }
 
@@ -115,7 +153,43 @@ _transform_android_manifest = rule(
     implementation = _transform_android_manifest_impl,
 )
 
-def define_oppia_binary_flavor(flavor):
+def transform_android_manifest(
+        name,
+        input_file,
+        output_file,
+        build_flavor,
+        major_version,
+        minor_version,
+        version_code):
+    """
+    Generates a new transformation of the specified AndroidManifest.xml.
+
+    The transformed version of the manifest include an explicitly specified version code and
+    computed version name based on the specified major/minor version, flavor, and the most recent
+    develop branch hash.
+
+    Args:
+        name: str. The name of this transformation target.
+        input_file: target. The file target corresponding to the AndroidManifest.xml file to
+            transform.
+        output_file: str. The filename that should be generated as the transformed manifest.
+        build_flavor: str. The specific release flavor of this build of the app.
+        major_version: int. The major version of the app.
+        minor_version: int. The minor version of the app.
+        version_code: int. The version code of this flavor of the app.
+    """
+    _transform_android_manifest(
+        name = name,
+        input_file = input_file,
+        output_file = output_file,
+        git_meta_dir = "//:.git",
+        build_flavor = build_flavor,
+        major_version = major_version,
+        minor_version = minor_version,
+        version_code = version_code,
+    )
+
+def define_oppia_aab_binary_flavor(flavor):
     """
     Defines a new flavor of the Oppia Android app.
 
@@ -130,15 +204,14 @@ def define_oppia_binary_flavor(flavor):
         flavor: str. The name of the flavor of the app. Must correspond to an entry in
             AVAILABLE_FLAVORS.
     """
-    _transform_android_manifest(
+    transform_android_manifest(
         name = "oppia_%s_transformed_manifest" % flavor,
         input_file = _FLAVOR_METADATA[flavor]["manifest"],
         output_file = "AndroidManifest_transformed_%s.xml" % flavor,
-        git_meta_dir = "//:.git",
         build_flavor = flavor,
         major_version = MAJOR_VERSION,
         minor_version = MINOR_VERSION,
-        version_code = VERSION_CODE,
+        version_code = _FLAVOR_METADATA[flavor]["version_code"],
     )
     oppia_android_application(
         name = "oppia_%s" % flavor,
@@ -153,6 +226,7 @@ def define_oppia_binary_flavor(flavor):
             "targetSdkVersion": "%d" % _FLAVOR_METADATA[flavor]["target_sdk_version"],
         },
         multidex = _FLAVOR_METADATA[flavor]["multidex"],
+        main_dex_list = _FLAVOR_METADATA[flavor].get("main_dex_list"),
         proguard_generate_mapping = True if len(_FLAVOR_METADATA[flavor]["proguard_specs"]) != 0 else False,
         proguard_specs = _FLAVOR_METADATA[flavor]["proguard_specs"],
         shrink_resources = True if len(_FLAVOR_METADATA[flavor]["proguard_specs"]) != 0 else False,
diff --git a/config/kitkat_main_dex_class_list.txt b/config/kitkat_main_dex_class_list.txt
new file mode 100644
index 00000000000..fd7f268faeb
--- /dev/null
+++ b/config/kitkat_main_dex_class_list.txt
@@ -0,0 +1,62 @@
+androidx/multidex/BuildConfig.class
+androidx/multidex/MultiDex$V19.class
+androidx/multidex/MultiDex.class
+androidx/multidex/MultiDexApplication.class
+androidx/multidex/MultiDexExtractor$1.class
+androidx/multidex/MultiDexExtractor$ExtractedDex.class
+androidx/multidex/MultiDexExtractor.class
+androidx/multidex/ZipUtil$CentralDirectory.class
+androidx/multidex/ZipUtil.class
+androidx/work/Configuration$Provider.class
+androidx/work/Configuration.class
+androidx/work/WorkManager.class
+com/google/firebase/FirebaseApp.class
+javax/inject/Provider.class
+kotlin/Function.class
+kotlin/jvm/functions/Function0.class
+kotlin/jvm/internal/FunctionBase.class
+kotlin/jvm/internal/Intrinsics.class
+kotlin/jvm/internal/Lambda.class
+kotlin/Lazy.class
+kotlin/LazyKt.class
+kotlin/LazyKt__LazyJVMKt.class
+kotlin/LazyKt__LazyKt.class
+kotlin/SynchronizedLazyImpl.class
+kotlin/UNINITIALIZED_VALUE.class
+org/oppia/android/app/activity/ActivityComponent.class
+org/oppia/android/app/activity/ActivityComponentFactory.class
+org/oppia/android/app/activity/ActivityComponentImpl$Builder.class
+org/oppia/android/app/activity/ActivityComponentImpl.class
+org/oppia/android/app/application/ApplicationComponent$Builder.class
+org/oppia/android/app/application/ApplicationComponent.class
+org/oppia/android/app/application/ApplicationInjector.class
+org/oppia/android/app/application/ApplicationInjectorProvider$DefaultImpls.class
+org/oppia/android/app/application/ApplicationInjectorProvider.class
+org/oppia/android/app/application/ApplicationModule.class
+org/oppia/android/app/application/ApplicationModule_ProvideApplicationContextFactory.class
+org/oppia/android/app/application/ApplicationModule_ProvideContextFactory.class
+org/oppia/android/app/application/DaggerApplicationComponent$1.class
+org/oppia/android/app/application/DaggerApplicationComponent$ActivityComponentImplBuilder.class
+org/oppia/android/app/application/DaggerApplicationComponent$ActivityComponentImplImpl$1.class
+org/oppia/android/app/application/DaggerApplicationComponent$ActivityComponentImplImpl$FragmentComponentImplBuilder.class
+org/oppia/android/app/application/DaggerApplicationComponent$ActivityComponentImplImpl$FragmentComponentImplImpl$1.class
+org/oppia/android/app/application/DaggerApplicationComponent$ActivityComponentImplImpl$FragmentComponentImplImpl$ViewComponentImplBuilder.class
+org/oppia/android/app/application/DaggerApplicationComponent$ActivityComponentImplImpl$FragmentComponentImplImpl.class
+org/oppia/android/app/application/DaggerApplicationComponent$ActivityComponentImplImpl.class
+org/oppia/android/app/application/DaggerApplicationComponent$Builder.class
+org/oppia/android/app/application/DaggerApplicationComponent$PresentGuavaOptionalInstanceProvider.class
+org/oppia/android/app/application/DaggerApplicationComponent.class
+org/oppia/android/app/application/OppiaApplication$component$2.class
+org/oppia/android/app/application/OppiaApplication.class
+org/oppia/android/app/translation/AppLanguageActivityInjector.class
+org/oppia/android/app/translation/AppLanguageActivityInjectorProvider.class
+org/oppia/android/app/translation/AppLanguageApplicationInjector.class
+org/oppia/android/app/translation/AppLanguageApplicationInjectorProvider.class
+org/oppia/android/app/utility/datetime/DateTimeUtil$Injector.class
+org/oppia/android/domain/locale/LocaleApplicationInjector.class
+org/oppia/android/domain/locale/LocaleApplicationInjectorProvider.class
+org/oppia/android/domain/oppialogger/ApplicationStartupListener.class
+org/oppia/android/util/data/DataProvidersInjector.class
+org/oppia/android/util/data/DataProvidersInjectorProvider.class
+org/oppia/android/util/system/OppiaClockInjector.class
+org/oppia/android/util/system/OppiaClockInjectorProvider.class
diff --git a/data/build.gradle b/data/build.gradle
index ec8fa21ac46..16bc0587325 100644
--- a/data/build.gradle
+++ b/data/build.gradle
@@ -66,6 +66,7 @@ dependencies {
       'androidx.appcompat:appcompat:1.0.2',
       'com.android.support:multidex:1.0.3',
       'com.google.dagger:dagger:2.24',
+      'com.google.guava:guava:28.1-android',
       'com.google.protobuf:protobuf-javalite:3.17.3',
       'com.squareup.moshi:moshi-kotlin:1.11.0',
       'com.squareup.okhttp3:okhttp:4.1.0',
diff --git a/data/src/main/java/org/oppia/android/data/backends/gae/BUILD.bazel b/data/src/main/java/org/oppia/android/data/backends/gae/BUILD.bazel
index 33776d70013..991bb9cb694 100644
--- a/data/src/main/java/org/oppia/android/data/backends/gae/BUILD.bazel
+++ b/data/src/main/java/org/oppia/android/data/backends/gae/BUILD.bazel
@@ -78,6 +78,7 @@ kt_android_library(
         ":network_interceptors",
         ":oppia_retrofit",
         "//data/src/main/java/org/oppia/android/data/backends/gae/api",
+        "//third_party:com_google_guava_guava",
         "//third_party:com_squareup_retrofit2_converter-moshi",
     ],
 )
diff --git a/data/src/main/java/org/oppia/android/data/backends/gae/NetworkModule.kt b/data/src/main/java/org/oppia/android/data/backends/gae/NetworkModule.kt
index 7584f5059ef..0d6205a6a94 100644
--- a/data/src/main/java/org/oppia/android/data/backends/gae/NetworkModule.kt
+++ b/data/src/main/java/org/oppia/android/data/backends/gae/NetworkModule.kt
@@ -1,5 +1,8 @@
 package org.oppia.android.data.backends.gae
 
+import android.annotation.SuppressLint
+import android.os.Build
+import com.google.common.base.Optional
 import dagger.Module
 import dagger.Provides
 import okhttp3.OkHttpClient
@@ -18,11 +21,7 @@ import javax.inject.Singleton
  */
 @Module
 class NetworkModule {
-
-  /**
-   * Provides the Retrofit object.
-   * @return the Retrofit object
-   */
+  @SuppressLint("ObsoleteSdkInt") // AS warning is incorrect in this context.
   @OppiaRetrofit
   @Provides
   @Singleton
@@ -30,58 +29,52 @@ class NetworkModule {
     jsonPrefixNetworkInterceptor: JsonPrefixNetworkInterceptor,
     remoteAuthNetworkInterceptor: RemoteAuthNetworkInterceptor,
     @BaseUrl baseUrl: String
-  ): Retrofit {
-    val client = OkHttpClient.Builder()
-      .addInterceptor(jsonPrefixNetworkInterceptor)
-      .addInterceptor(remoteAuthNetworkInterceptor)
-      .build()
+  ): Optional<Retrofit> {
+    // TODO(#1720): Make this a compile-time dep once Hilt provides it as an option.
+    return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
+      val client = OkHttpClient.Builder()
+        .addInterceptor(jsonPrefixNetworkInterceptor)
+        .addInterceptor(remoteAuthNetworkInterceptor)
+        .build()
 
-    return Retrofit.Builder()
-      .baseUrl(baseUrl)
-      .addConverterFactory(MoshiConverterFactory.create())
-      .client(client)
-      .build()
+      Optional.of(
+        Retrofit.Builder()
+          .baseUrl(baseUrl)
+          .addConverterFactory(MoshiConverterFactory.create())
+          .client(client)
+          .build()
+      )
+    } else Optional.absent()
   }
 
-  /**
-   * Provides the Topic service implementation.
-   * @param retrofit the Retrofit object used to instantiate the service
-   * @return the Topic service implementation.
-   */
   @Provides
   @Singleton
-  fun provideTopicService(@OppiaRetrofit retrofit: Retrofit): TopicService {
-    return retrofit.create(TopicService::class.java)
+  fun provideTopicService(@OppiaRetrofit retrofit: Optional<Retrofit>): Optional<TopicService> {
+    return retrofit.map { it.create(TopicService::class.java) }
   }
 
-  /**
-   * Provides the Classroom service implementation.
-   * @param retrofit the Retrofit object used to instantiate the service
-   * @return the Classroom service implementation.
-   */
   @Provides
   @Singleton
-  fun provideClassroomService(@OppiaRetrofit retrofit: Retrofit): ClassroomService {
-    return retrofit.create(ClassroomService::class.java)
+  fun provideClassroomService(
+    @OppiaRetrofit retrofit: Optional<Retrofit>
+  ): Optional<ClassroomService> {
+    return retrofit.map { it.create(ClassroomService::class.java) }
   }
 
-  // Provides the Feedback Reporting service implementation.
   @Provides
   @Singleton
-  fun provideFeedbackReportingService(@OppiaRetrofit retrofit: Retrofit): FeedbackReportingService {
-    return retrofit.create(FeedbackReportingService::class.java)
+  fun provideFeedbackReportingService(
+    @OppiaRetrofit retrofit: Optional<Retrofit>
+  ): Optional<FeedbackReportingService> {
+    return retrofit.map { it.create(FeedbackReportingService::class.java) }
   }
 
-  /**
-   * Provides the [PlatformParameterService] implementation.
-   *
-   * @param retrofit the Retrofit object used to instantiate the service
-   * @return the [PlatformParameterService] implementation
-   */
   @Provides
   @Singleton
-  fun providePlatformParameterService(@OppiaRetrofit retrofit: Retrofit): PlatformParameterService {
-    return retrofit.create(PlatformParameterService::class.java)
+  fun providePlatformParameterService(
+    @OppiaRetrofit retrofit: Optional<Retrofit>
+  ): Optional<PlatformParameterService> {
+    return retrofit.map { it.create(PlatformParameterService::class.java) }
   }
 
   // Provides the API key to use in authenticating remote messages sent or received. This will be
@@ -89,4 +82,9 @@ class NetworkModule {
   @Provides
   @NetworkApiKey
   fun provideNetworkApiKey(): String = ""
+
+  private companion object {
+    private fun <T, V> Optional<T>.map(mapFunc: (T) -> V): Optional<V> =
+      transform { mapFunc(checkNotNull(it)) } // Paylaod should never actually be null.
+  }
 }
diff --git a/data/src/test/java/org/oppia/android/data/backends/gae/NetworkModuleTest.kt b/data/src/test/java/org/oppia/android/data/backends/gae/NetworkModuleTest.kt
new file mode 100644
index 00000000000..40e19c800fc
--- /dev/null
+++ b/data/src/test/java/org/oppia/android/data/backends/gae/NetworkModuleTest.kt
@@ -0,0 +1,161 @@
+package org.oppia.android.data.backends.gae
+
+import android.app.Application
+import android.content.Context
+import android.os.Build
+import androidx.test.core.app.ApplicationProvider
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.google.common.base.Optional
+import com.google.common.truth.Truth.assertThat
+import dagger.BindsInstance
+import dagger.Component
+import dagger.Module
+import dagger.Provides
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.oppia.android.data.backends.gae.api.ClassroomService
+import org.oppia.android.data.backends.gae.api.FeedbackReportingService
+import org.oppia.android.data.backends.gae.api.PlatformParameterService
+import org.oppia.android.data.backends.gae.api.TopicService
+import org.robolectric.annotation.Config
+import org.robolectric.annotation.LooperMode
+import retrofit2.Retrofit
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/** Tests for [NetworkModule]. */
+@RunWith(AndroidJUnit4::class)
+@LooperMode(LooperMode.Mode.PAUSED)
+@Config(application = NetworkModuleTest.TestApplication::class)
+class NetworkModuleTest {
+  @field:[Inject NetworkApiKey]
+  lateinit var networkApiKey: String
+
+  @Before
+  fun setUp() {
+    setUpTestApplicationComponent()
+  }
+
+  @Test
+  @Config(sdk = [Build.VERSION_CODES.LOLLIPOP])
+  fun testRetrofitInstance_lollipop_isProvided() {
+    assertThat(getTestApplication().getRetrofit()).isPresent()
+  }
+
+  @Test
+  @Config(sdk = [Build.VERSION_CODES.KITKAT])
+  fun testRetrofitInstance_kitkat_isEmpty() {
+    assertThat(getTestApplication().getRetrofit()).isAbsent()
+  }
+
+  @Test
+  @Config(sdk = [Build.VERSION_CODES.LOLLIPOP])
+  fun testTopicService_lollipop_isProvided() {
+    assertThat(getTestApplication().getTopicService()).isPresent()
+  }
+
+  @Test
+  @Config(sdk = [Build.VERSION_CODES.KITKAT])
+  fun testTopicService_kitkat_isEmpty() {
+    assertThat(getTestApplication().getTopicService()).isAbsent()
+  }
+
+  @Test
+  @Config(sdk = [Build.VERSION_CODES.LOLLIPOP])
+  fun testClassroomService_lollipop_isProvided() {
+    assertThat(getTestApplication().getClassroomService()).isPresent()
+  }
+
+  @Test
+  @Config(sdk = [Build.VERSION_CODES.KITKAT])
+  fun testClassroomService_kitkat_isEmpty() {
+    assertThat(getTestApplication().getClassroomService()).isAbsent()
+  }
+
+  @Test
+  @Config(sdk = [Build.VERSION_CODES.LOLLIPOP])
+  fun testFeedbackReportingService_lollipop_isProvided() {
+    assertThat(getTestApplication().getFeedbackReportingService()).isPresent()
+  }
+
+  @Test
+  @Config(sdk = [Build.VERSION_CODES.KITKAT])
+  fun testFeedbackReportingService_kitkat_isEmpty() {
+    assertThat(getTestApplication().getFeedbackReportingService()).isAbsent()
+  }
+
+  @Test
+  @Config(sdk = [Build.VERSION_CODES.LOLLIPOP])
+  fun testPlatformParameterService_lollipop_isProvided() {
+    assertThat(getTestApplication().getPlatformParameterService()).isPresent()
+  }
+
+  @Test
+  @Config(sdk = [Build.VERSION_CODES.KITKAT])
+  fun testPlatformParameterService_kitkat_isEmpty() {
+    assertThat(getTestApplication().getPlatformParameterService()).isAbsent()
+  }
+
+  @Test
+  fun testNetworkApiKey_isEmpty() {
+    // The network API key is empty by default on developer builds.
+    assertThat(networkApiKey).isEmpty()
+  }
+
+  private fun getTestApplication() = ApplicationProvider.getApplicationContext<TestApplication>()
+
+  private fun setUpTestApplicationComponent() {
+    getTestApplication().inject(this)
+  }
+
+  @Module
+  class TestModule {
+    @Provides
+    @Singleton
+    fun provideContext(application: Application): Context {
+      return application
+    }
+  }
+
+  @Singleton
+  @Component(
+    modules = [
+      TestModule::class, NetworkModule::class, NetworkConfigProdModule::class
+    ]
+  )
+
+  interface TestApplicationComponent {
+    @Component.Builder
+    interface Builder {
+      @BindsInstance
+      fun setApplication(application: Application): Builder
+      fun build(): TestApplicationComponent
+    }
+
+    fun inject(networkModuleTest: NetworkModuleTest)
+    @OppiaRetrofit fun getRetrofit(): Optional<Retrofit>
+    fun getTopicService(): Optional<TopicService>
+    fun getClassroomService(): Optional<ClassroomService>
+    fun getFeedbackReportingService(): Optional<FeedbackReportingService>
+    fun getPlatformParameterService(): Optional<PlatformParameterService>
+  }
+
+  class TestApplication : Application() {
+    private val component: TestApplicationComponent by lazy {
+      DaggerNetworkModuleTest_TestApplicationComponent.builder()
+        .setApplication(this)
+        .build()
+    }
+
+    fun inject(networkModuleTest: NetworkModuleTest) {
+      component.inject(networkModuleTest)
+    }
+
+    fun getRetrofit() = component.getRetrofit()
+    fun getTopicService() = component.getTopicService()
+    fun getClassroomService() = component.getClassroomService()
+    fun getFeedbackReportingService() = component.getFeedbackReportingService()
+    fun getPlatformParameterService() = component.getPlatformParameterService()
+  }
+}
diff --git a/domain/src/main/java/org/oppia/android/domain/platformparameter/syncup/PlatformParameterSyncUpWorker.kt b/domain/src/main/java/org/oppia/android/domain/platformparameter/syncup/PlatformParameterSyncUpWorker.kt
index a2735094fd3..83bb3d4b274 100644
--- a/domain/src/main/java/org/oppia/android/domain/platformparameter/syncup/PlatformParameterSyncUpWorker.kt
+++ b/domain/src/main/java/org/oppia/android/domain/platformparameter/syncup/PlatformParameterSyncUpWorker.kt
@@ -3,6 +3,7 @@ package org.oppia.android.domain.platformparameter.syncup
 import android.content.Context
 import androidx.work.ListenableWorker
 import androidx.work.WorkerParameters
+import com.google.common.base.Optional
 import com.google.common.util.concurrent.ListenableFuture
 import com.google.common.util.concurrent.SettableFuture
 import kotlinx.coroutines.CoroutineDispatcher
@@ -27,7 +28,7 @@ class PlatformParameterSyncUpWorker private constructor(
   context: Context,
   params: WorkerParameters,
   private val platformParameterController: PlatformParameterController,
-  private val platformParameterService: PlatformParameterService,
+  private val platformParameterService: Optional<PlatformParameterService>,
   private val oppiaLogger: OppiaLogger,
   private val exceptionsController: ExceptionsController,
   @BackgroundDispatcher private val backgroundDispatcher: CoroutineDispatcher
@@ -91,30 +92,38 @@ class PlatformParameterSyncUpWorker private constructor(
   }
 
   /** Synchronously executes the network request to get platform parameters from the Oppia backend */
-  private fun makeNetworkCallForPlatformParameters(): Response<Map<String, Any>> {
-    return platformParameterService.getPlatformParametersByVersion(
-      applicationContext.getVersionName()
-    ).execute()
+  private fun makeNetworkCallForPlatformParameters(): Optional<Response<Map<String, Any>>?> {
+    return platformParameterService.transform { service ->
+      service?.getPlatformParametersByVersion(
+        applicationContext.getVersionName()
+      )?.execute()
+    }
   }
 
   /** Extracts platform parameters from the remote service and stores them in the cache store */
   private suspend fun refreshPlatformParameters(): Result {
     return try {
-      val response = makeNetworkCallForPlatformParameters()
-      val responseBody = checkNotNull(response.body())
-      val platformParameterList = parseNetworkResponse(responseBody)
-      if (platformParameterList.isEmpty()) {
-        throw IllegalArgumentException(EMPTY_RESPONSE_EXCEPTION_MSG)
-      }
-      val cachingResult = platformParameterController
-        .updatePlatformParameterDatabase(platformParameterList)
-        .retrieveData()
-      if (cachingResult.isFailure()) {
-        throw IllegalStateException(cachingResult.getErrorOrNull())
+      val optionalResponse = makeNetworkCallForPlatformParameters()
+      val response = optionalResponse.orNull()
+      if (response != null) {
+        val responseBody = checkNotNull(response.body())
+        val platformParameterList = parseNetworkResponse(responseBody)
+        if (platformParameterList.isEmpty()) {
+          throw IllegalArgumentException(EMPTY_RESPONSE_EXCEPTION_MSG)
+        }
+        val cachingResult = platformParameterController
+          .updatePlatformParameterDatabase(platformParameterList)
+          .retrieveData()
+        if (cachingResult.isFailure()) {
+          throw IllegalStateException(cachingResult.getErrorOrNull())
+        }
+        Result.success()
+      } else {
+        oppiaLogger.e(TAG, "Failed to fetch platform parameters (no network stack available)")
+        Result.failure()
       }
-      Result.success()
     } catch (e: Exception) {
-      oppiaLogger.e(TAG, "Failed to fetch the Platform Parameters", e)
+      oppiaLogger.e(TAG, "Failed to fetch platform parameters", e)
       exceptionsController.logNonFatalException(e)
       Result.failure()
     }
@@ -123,7 +132,7 @@ class PlatformParameterSyncUpWorker private constructor(
   /** Creates an instance of [PlatformParameterSyncUpWorker] by properly injecting dependencies. */
   class Factory @Inject constructor(
     private val platformParameterController: PlatformParameterController,
-    private val platformParameterService: PlatformParameterService,
+    private val platformParameterService: Optional<PlatformParameterService>,
     private val oppiaLogger: OppiaLogger,
     private val exceptionsController: ExceptionsController,
     @BackgroundDispatcher private val backgroundDispatcher: CoroutineDispatcher
diff --git a/domain/src/test/java/org/oppia/android/domain/platformparameter/syncup/PlatformParameterSyncUpWorkManagerInitializerTest.kt b/domain/src/test/java/org/oppia/android/domain/platformparameter/syncup/PlatformParameterSyncUpWorkManagerInitializerTest.kt
index 1f8389552cc..285f42a52e2 100644
--- a/domain/src/test/java/org/oppia/android/domain/platformparameter/syncup/PlatformParameterSyncUpWorkManagerInitializerTest.kt
+++ b/domain/src/test/java/org/oppia/android/domain/platformparameter/syncup/PlatformParameterSyncUpWorkManagerInitializerTest.kt
@@ -13,6 +13,7 @@ import androidx.work.NetworkType
 import androidx.work.WorkManager
 import androidx.work.testing.SynchronousExecutor
 import androidx.work.testing.WorkManagerTestInitHelper
+import com.google.common.base.Optional
 import com.google.common.truth.Truth.assertThat
 import dagger.BindsInstance
 import dagger.Component
@@ -200,17 +201,19 @@ class PlatformParameterSyncUpWorkManagerInitializerTest {
       jsonPrefixNetworkInterceptor: JsonPrefixNetworkInterceptor,
       remoteAuthNetworkInterceptor: RemoteAuthNetworkInterceptor,
       @BaseUrl baseUrl: String
-    ): Retrofit {
+    ): Optional<Retrofit> {
       val client = OkHttpClient.Builder()
         .addInterceptor(jsonPrefixNetworkInterceptor)
         .addInterceptor(remoteAuthNetworkInterceptor)
         .build()
 
-      return Retrofit.Builder()
-        .baseUrl(baseUrl)
-        .addConverterFactory(MoshiConverterFactory.create())
-        .client(client)
-        .build()
+      return Optional.of(
+        Retrofit.Builder()
+          .baseUrl(baseUrl)
+          .addConverterFactory(MoshiConverterFactory.create())
+          .client(client)
+          .build()
+      )
     }
 
     @Provides
@@ -218,9 +221,11 @@ class PlatformParameterSyncUpWorkManagerInitializerTest {
     fun provideNetworkApiKey(): String = ""
 
     @Provides
-    fun provideMockPlatformParameterService(mockRetrofit: MockRetrofit): PlatformParameterService {
+    fun provideMockPlatformParameterService(
+      mockRetrofit: MockRetrofit
+    ): Optional<PlatformParameterService> {
       val delegate = mockRetrofit.create(PlatformParameterService::class.java)
-      return MockPlatformParameterService(delegate)
+      return Optional.of(MockPlatformParameterService(delegate))
     }
   }
 
diff --git a/domain/src/test/java/org/oppia/android/domain/platformparameter/syncup/PlatformParameterSyncUpWorkerTest.kt b/domain/src/test/java/org/oppia/android/domain/platformparameter/syncup/PlatformParameterSyncUpWorkerTest.kt
index 6c4d0afd4c5..70ccd1e8c08 100644
--- a/domain/src/test/java/org/oppia/android/domain/platformparameter/syncup/PlatformParameterSyncUpWorkerTest.kt
+++ b/domain/src/test/java/org/oppia/android/domain/platformparameter/syncup/PlatformParameterSyncUpWorkerTest.kt
@@ -15,6 +15,7 @@ import androidx.work.WorkInfo
 import androidx.work.WorkManager
 import androidx.work.testing.SynchronousExecutor
 import androidx.work.testing.WorkManagerTestInitHelper
+import com.google.common.base.Optional
 import com.google.common.truth.Truth.assertThat
 import dagger.BindsInstance
 import dagger.Component
@@ -400,17 +401,19 @@ class PlatformParameterSyncUpWorkerTest {
       jsonPrefixNetworkInterceptor: JsonPrefixNetworkInterceptor,
       remoteAuthNetworkInterceptor: RemoteAuthNetworkInterceptor,
       @BaseUrl baseUrl: String
-    ): Retrofit {
+    ): Optional<Retrofit> {
       val client = OkHttpClient.Builder()
         .addInterceptor(jsonPrefixNetworkInterceptor)
         .addInterceptor(remoteAuthNetworkInterceptor)
         .build()
 
-      return Retrofit.Builder()
-        .baseUrl(baseUrl)
-        .addConverterFactory(MoshiConverterFactory.create())
-        .client(client)
-        .build()
+      return Optional.of(
+        Retrofit.Builder()
+          .baseUrl(baseUrl)
+          .addConverterFactory(MoshiConverterFactory.create())
+          .client(client)
+          .build()
+      )
     }
 
     @Provides
@@ -418,9 +421,11 @@ class PlatformParameterSyncUpWorkerTest {
     fun provideNetworkApiKey(): String = ""
 
     @Provides
-    fun provideMockPlatformParameterService(mockRetrofit: MockRetrofit): PlatformParameterService {
+    fun provideMockPlatformParameterService(
+      mockRetrofit: MockRetrofit
+    ): Optional<PlatformParameterService> {
       val delegate = mockRetrofit.create(PlatformParameterService::class.java)
-      return MockPlatformParameterService(delegate)
+      return Optional.of(MockPlatformParameterService(delegate))
     }
   }
 
diff --git a/instrumentation/src/java/AndroidManifest.xml b/instrumentation/src/java/AndroidManifest.xml
index b089ccec5ef..847486b0240 100644
--- a/instrumentation/src/java/AndroidManifest.xml
+++ b/instrumentation/src/java/AndroidManifest.xml
@@ -97,7 +97,7 @@
     <activity
       android:name=".app.profile.AddProfileActivity"
       android:label="@string/add_profile_activity_label"
-      android:theme="@style/OppiaThemeNoActionBarColorAccentColorPrimary" />
+      android:theme="@style/OppiaThemeWithoutActionBarColorAccentColorPrimary" />
     <activity
       android:name=".app.profile.AdminAuthActivity"
       android:label="@string/admin_auth_activity_access_controls_title"
diff --git a/scripts/assets/file_content_validation_checks.textproto b/scripts/assets/file_content_validation_checks.textproto
index 2e45a7a26f9..0700602b594 100644
--- a/scripts/assets/file_content_validation_checks.textproto
+++ b/scripts/assets/file_content_validation_checks.textproto
@@ -98,7 +98,13 @@ file_content_checks {
 file_content_checks {
   file_path_regex: ".+?.kt"
   prohibited_content_regex: "android.text.BidiFormatter"
-  failure_message: "Do not use Android's BidiFormatter directly. Instead, use the wrapper utility OppiaBidiFormatter so that tests can verify that formatting actually occurs on select strings."
+  failure_message: "Do not use Android's BidiFormatter directly. Instead, use AndroidX's BidiFormatter for KitKat compatibility."
+  exempted_file_name: "scripts/src/javatests/org/oppia/android/scripts/regex/RegexPatternValidationCheckTest.kt"
+}
+file_content_checks {
+  file_path_regex: ".+?.kt"
+  prohibited_content_regex: "androidx.core.text.BidiFormatter"
+  failure_message: "Do not use AndroidX's BidiFormatter directly. Instead, use the wrapper utility OppiaBidiFormatter so that tests can verify that formatting actually occurs on select strings."
   exempted_file_name: "scripts/src/javatests/org/oppia/android/scripts/regex/RegexPatternValidationCheckTest.kt"
   exempted_file_name: "testing/src/main/java/org/oppia/android/testing/robolectric/ShadowBidiFormatter.kt"
   exempted_file_name: "testing/src/test/java/org/oppia/android/testing/robolectric/ShadowBidiFormatterTest.kt"
@@ -181,6 +187,17 @@ file_content_checks {
   prohibited_content_regex: "android:configChanges"
   failure_message: "Never explicitly handle configuration changes. Instead, use saved instance states for retaining state across rotations. For other types of configuration changes, follow up with the developer mailing list with how to proceed if you think this is a legitimate case."
 }
+file_content_checks {
+  file_path_regex: ".+?.xml"
+  prohibited_content_regex: "(android:drawableStart)|(android:drawableEnd)|(android:drawableTop)|(android:drawableBottom)|(android:src)"
+  failure_message: "Drawable start/end/top/bottom & image source should use the compat versions, instead, e.g.: app:drawableStartCompat or app:srcCompat, to ensure that vector drawables can load properly in SDK <21 environments."
+}
+file_content_checks {
+  file_path_regex: ".+?.kt"
+  prohibited_content_regex: "java.util.Optional"
+  failure_message: "Prefer using com.google.common.base.Optional (Guava's Optional) since desugaring has some incompatibilities between Bazel & KitKat builds."
+  exempted_file_name: "scripts/src/javatests/org/oppia/android/scripts/regex/RegexPatternValidationCheckTest.kt"
+}
 file_content_checks {
   file_path_regex: ".+?.kt"
   prohibited_content_regex: "java\\.util\\.Calendar"
diff --git a/scripts/assets/test_file_exemptions.textproto b/scripts/assets/test_file_exemptions.textproto
index 4a85b76adab..3bcb76f2bd2 100644
--- a/scripts/assets/test_file_exemptions.textproto
+++ b/scripts/assets/test_file_exemptions.textproto
@@ -507,7 +507,6 @@ exempted_file_path: "app/src/test/java/org/oppia/android/app/testing/player/spli
 exempted_file_path: "data/src/main/java/org/oppia/android/data/backends/gae/BaseUrl.kt"
 exempted_file_path: "data/src/main/java/org/oppia/android/data/backends/gae/Constants.kt"
 exempted_file_path: "data/src/main/java/org/oppia/android/data/backends/gae/NetworkApiKey.kt"
-exempted_file_path: "data/src/main/java/org/oppia/android/data/backends/gae/NetworkModule.kt"
 exempted_file_path: "data/src/main/java/org/oppia/android/data/backends/gae/OppiaRetrofit.kt"
 exempted_file_path: "data/src/main/java/org/oppia/android/data/backends/gae/XssiPrefix.kt"
 exempted_file_path: "data/src/main/java/org/oppia/android/data/backends/gae/model/GaeAnswerGroup.kt"
diff --git a/scripts/src/javatests/org/oppia/android/scripts/regex/RegexPatternValidationCheckTest.kt b/scripts/src/javatests/org/oppia/android/scripts/regex/RegexPatternValidationCheckTest.kt
index 64259eb57f8..316fd0ef432 100644
--- a/scripts/src/javatests/org/oppia/android/scripts/regex/RegexPatternValidationCheckTest.kt
+++ b/scripts/src/javatests/org/oppia/android/scripts/regex/RegexPatternValidationCheckTest.kt
@@ -61,7 +61,10 @@ class RegexPatternValidationCheckTest {
   private val translatablePluralsGoInMainFileErrorMessage =
     "All plurals outside strings.xml must be marked as not translatable, or moved to strings.xml."
   private val importingAndroidBidiFormatterErrorMessage =
-    "Do not use Android's BidiFormatter directly. Instead, use the wrapper utility" +
+    "Do not use Android's BidiFormatter directly. Instead, use AndroidX's BidiFormatter for" +
+      " KitKat compatibility."
+  private val importingAndroidXBidiFormatterErrorMessage =
+    "Do not use AndroidX's BidiFormatter directly. Instead, use the wrapper utility" +
       " OppiaBidiFormatter so that tests can verify that formatting actually occurs on select" +
       " strings."
   private val useStringFormattingFunctionInKotlinOrJavaErrorMessage =
@@ -96,6 +99,13 @@ class RegexPatternValidationCheckTest {
     "Never explicitly handle configuration changes. Instead, use saved instance states for" +
       " retaining state across rotations. For other types of configuration changes, follow up" +
       " with the developer mailing list with how to proceed if you think this is a legitimate case."
+  private val nonCompatDrawableUsedErrorMessage =
+    "Drawable start/end/top/bottom & image source should use the compat versions, instead, e.g.:" +
+      " app:drawableStartCompat or app:srcCompat, to ensure that vector drawables can load" +
+      " properly in SDK <21 environments."
+  private val useJava8OptionalErrorMessage =
+    "Prefer using com.google.common.base.Optional (Guava's Optional) since desugaring has some" +
+      " incompatibilities between Bazel & KitKat builds."
   private val useJavaCalendarErrorMessage =
     "Don't use Calendar directly. Instead, use OppiaClock and/or OppiaLocale for" +
       " calendar-specific operations."
@@ -940,7 +950,7 @@ class RegexPatternValidationCheckTest {
   }
 
   @Test
-  fun testFileContent_bidiFormatterImport_fileContentIsNotCorrect() {
+  fun testFileContent_androidBidiFormatterImport_fileContentIsNotCorrect() {
     val prohibitedContent = "import android.text.BidiFormatter"
     tempFolder.newFolder("testfiles", "data", "src", "main")
     val stringFilePath = "data/src/main/SomeController.kt"
@@ -960,6 +970,27 @@ class RegexPatternValidationCheckTest {
       )
   }
 
+  @Test
+  fun testFileContent_androidXBidiFormatterImport_fileContentIsNotCorrect() {
+    val prohibitedContent = "import androidx.core.text.BidiFormatter"
+    tempFolder.newFolder("testfiles", "data", "src", "main")
+    val stringFilePath = "data/src/main/SomeController.kt"
+    tempFolder.newFile("testfiles/$stringFilePath").writeText(prohibitedContent)
+
+    val exception = assertThrows(Exception::class) {
+      runScript()
+    }
+
+    assertThat(exception).hasMessageThat().contains(REGEX_CHECK_FAILED_OUTPUT_INDICATOR)
+    assertThat(outContent.toString().trim())
+      .isEqualTo(
+        """
+        $stringFilePath:1: $importingAndroidXBidiFormatterErrorMessage
+        $wikiReferenceNote
+        """.trimIndent()
+      )
+  }
+
   @Test
   fun testFileContent_untranslatableString_outsidePrimaryStringsFile_fileContentIsCorrect() {
     val prohibitedContent = "<string name=\"test\">Translatable</string>"
@@ -1431,6 +1462,63 @@ class RegexPatternValidationCheckTest {
       )
   }
 
+  @Test
+  fun testFileContent_nonCompatDrawables_fileContentIsNotCorrect() {
+    val prohibitedContent =
+      """
+        android:drawableStart="@drawable/example_drawable"
+        app:drawableStartCompat="@drawable/example_drawable"
+        android:drawableEnd="@drawable/example_drawable"
+        app:drawableEndCompat="@drawable/example_drawable"
+        android:drawableTop="@drawable/example_drawable"
+        app:drawableTopCompat="@drawable/example_drawable"
+        android:drawableBottom="@drawable/example_drawable"
+        app:drawableBottomCompat="@drawable/example_drawable"
+        android:src="@drawable/example_drawable"
+        app:srcCompat="@drawable/example_drawable"
+      """.trimIndent()
+    val fileContainsSupportLibraryImport = "test_layout.xml"
+    tempFolder.newFile("testfiles/$fileContainsSupportLibraryImport").writeText(prohibitedContent)
+
+    val exception = assertThrows(Exception::class) {
+      runScript()
+    }
+
+    assertThat(exception).hasMessageThat().contains(REGEX_CHECK_FAILED_OUTPUT_INDICATOR)
+    assertThat(outContent.toString().trim())
+      .isEqualTo(
+        """
+        $fileContainsSupportLibraryImport:1: $nonCompatDrawableUsedErrorMessage
+        $fileContainsSupportLibraryImport:3: $nonCompatDrawableUsedErrorMessage
+        $fileContainsSupportLibraryImport:5: $nonCompatDrawableUsedErrorMessage
+        $fileContainsSupportLibraryImport:7: $nonCompatDrawableUsedErrorMessage
+        $fileContainsSupportLibraryImport:9: $nonCompatDrawableUsedErrorMessage
+        $wikiReferenceNote
+        """.trimIndent()
+      )
+  }
+
+  @Test
+  fun testFileContent_java8OptionalImport_fileContentIsNotCorrect() {
+    val prohibitedContent = "import java.util.Optional"
+    tempFolder.newFolder("testfiles", "data", "src", "main")
+    val stringFilePath = "data/src/main/SomeController.kt"
+    tempFolder.newFile("testfiles/$stringFilePath").writeText(prohibitedContent)
+
+    val exception = assertThrows(Exception::class) {
+      runScript()
+    }
+
+    assertThat(exception).hasMessageThat().contains(REGEX_CHECK_FAILED_OUTPUT_INDICATOR)
+    assertThat(outContent.toString().trim())
+      .isEqualTo(
+        """
+        $stringFilePath:1: $useJava8OptionalErrorMessage
+        $wikiReferenceNote
+        """.trimIndent()
+      )
+  }
+
   @Test
   fun testFilenameAndContent_useProhibitedFileName_useProhibitedFileContent_multipleFailures() {
     tempFolder.newFolder("testfiles", "data", "src", "main")
diff --git a/testing/src/main/java/org/oppia/android/testing/network/RetrofitTestModule.kt b/testing/src/main/java/org/oppia/android/testing/network/RetrofitTestModule.kt
index 579eb35e6ab..70c570568c2 100644
--- a/testing/src/main/java/org/oppia/android/testing/network/RetrofitTestModule.kt
+++ b/testing/src/main/java/org/oppia/android/testing/network/RetrofitTestModule.kt
@@ -1,5 +1,6 @@
 package org.oppia.android.testing.network
 
+import com.google.common.base.Optional
 import dagger.Module
 import dagger.Provides
 import org.oppia.android.data.backends.gae.OppiaRetrofit
@@ -12,16 +13,22 @@ import javax.inject.Singleton
  * Dagger [Module] that provides specifically configured [MockRetrofit] instance to have zero
  * network failures to avoid unwanted test flakes. Tests may override this behavior if they
  * wish to test uncertain network conditions.
+ *
+ * Note that Retrofit may be absent from the builds in certain environments (such as KitKat).
+ * Attempting to inject [MockRetrofit] will verify that Retrofit is present, or otherwise fail. Do
+ * not inject [MockRetrofit] for tests where Retrofit is supposed to be absent.
  */
 @Module
 class RetrofitTestModule {
   @Provides
   @Singleton
-  fun provideMockRetrofit(@OppiaRetrofit retrofit: Retrofit): MockRetrofit {
+  fun provideMockRetrofit(@OppiaRetrofit retrofit: Optional<Retrofit>): MockRetrofit {
+    check(retrofit.isPresent) {
+      "Expected Retrofit to be present in order to create a MockRetrofit"
+    }
     val behavior = NetworkBehavior.create()
     behavior.setFailurePercent(0)
-
-    return MockRetrofit.Builder(retrofit).apply {
+    return MockRetrofit.Builder(retrofit.get()).apply {
       networkBehavior(behavior)
     }.build()
   }
diff --git a/testing/src/main/java/org/oppia/android/testing/robolectric/BUILD.bazel b/testing/src/main/java/org/oppia/android/testing/robolectric/BUILD.bazel
index af491298ca6..89c998daa24 100644
--- a/testing/src/main/java/org/oppia/android/testing/robolectric/BUILD.bazel
+++ b/testing/src/main/java/org/oppia/android/testing/robolectric/BUILD.bazel
@@ -45,6 +45,7 @@ kt_android_library(
         "//utility/src/test/java/org/oppia/android/util/locale/testing:__pkg__",
     ],
     deps = [
+        "//third_party:androidx_core_core",
         "//third_party:org_robolectric_robolectric",
     ],
 )
diff --git a/testing/src/main/java/org/oppia/android/testing/robolectric/ShadowBidiFormatter.kt b/testing/src/main/java/org/oppia/android/testing/robolectric/ShadowBidiFormatter.kt
index a24d0daaed3..a41507cf939 100644
--- a/testing/src/main/java/org/oppia/android/testing/robolectric/ShadowBidiFormatter.kt
+++ b/testing/src/main/java/org/oppia/android/testing/robolectric/ShadowBidiFormatter.kt
@@ -1,6 +1,6 @@
 package org.oppia.android.testing.robolectric
 
-import android.text.BidiFormatter
+import androidx.core.text.BidiFormatter
 import org.robolectric.annotation.Implementation
 import org.robolectric.annotation.Implements
 import org.robolectric.annotation.RealObject
diff --git a/testing/src/test/java/org/oppia/android/testing/robolectric/BUILD.bazel b/testing/src/test/java/org/oppia/android/testing/robolectric/BUILD.bazel
index 8e92cbfb7b0..144e4f00c59 100644
--- a/testing/src/test/java/org/oppia/android/testing/robolectric/BUILD.bazel
+++ b/testing/src/test/java/org/oppia/android/testing/robolectric/BUILD.bazel
@@ -14,6 +14,7 @@ oppia_android_test(
     deps = [
         ":dagger",
         "//testing/src/main/java/org/oppia/android/testing/robolectric:shadow_bidi_formatter",
+        "//third_party:androidx_core_core",
         "//third_party:androidx_test_ext_junit",
         "//third_party:com_google_truth_truth",
         "//third_party:junit_junit",
diff --git a/testing/src/test/java/org/oppia/android/testing/robolectric/ShadowBidiFormatterTest.kt b/testing/src/test/java/org/oppia/android/testing/robolectric/ShadowBidiFormatterTest.kt
index 5329921beba..9aaddb5201c 100644
--- a/testing/src/test/java/org/oppia/android/testing/robolectric/ShadowBidiFormatterTest.kt
+++ b/testing/src/test/java/org/oppia/android/testing/robolectric/ShadowBidiFormatterTest.kt
@@ -2,7 +2,8 @@ package org.oppia.android.testing.robolectric
 
 import android.app.Application
 import android.content.Context
-import android.text.BidiFormatter
+import android.os.Build
+import androidx.core.text.BidiFormatter
 import androidx.test.core.app.ApplicationProvider
 import androidx.test.ext.junit.runners.AndroidJUnit4
 import com.google.common.truth.Truth.assertThat
@@ -24,7 +25,9 @@ import javax.inject.Singleton
 @Suppress("FunctionName")
 @RunWith(AndroidJUnit4::class)
 @LooperMode(LooperMode.Mode.PAUSED)
-@Config(manifest = Config.NONE, shadows = [ShadowBidiFormatter::class])
+@Config(
+  manifest = Config.NONE, sdk = [Build.VERSION_CODES.P], shadows = [ShadowBidiFormatter::class]
+)
 class ShadowBidiFormatterTest {
   @Before
   fun setUp() {
diff --git a/utility/src/main/java/org/oppia/android/util/locale/BUILD.bazel b/utility/src/main/java/org/oppia/android/util/locale/BUILD.bazel
index ce75c3997cb..1522fe1a28a 100644
--- a/utility/src/main/java/org/oppia/android/util/locale/BUILD.bazel
+++ b/utility/src/main/java/org/oppia/android/util/locale/BUILD.bazel
@@ -52,6 +52,7 @@ kt_android_library(
         ":dagger",
         ":oppia_bidi_formatter",
         ":oppia_locale",
+        "//third_party:androidx_core_core",
         "//utility/src/main/java/org/oppia/android/util/system:oppia_clock",
     ],
 )
diff --git a/utility/src/main/java/org/oppia/android/util/locale/OppiaBidiFormatterImpl.kt b/utility/src/main/java/org/oppia/android/util/locale/OppiaBidiFormatterImpl.kt
index 5940339f9cf..00bfd6b28bb 100644
--- a/utility/src/main/java/org/oppia/android/util/locale/OppiaBidiFormatterImpl.kt
+++ b/utility/src/main/java/org/oppia/android/util/locale/OppiaBidiFormatterImpl.kt
@@ -1,6 +1,6 @@
 package org.oppia.android.util.locale
 
-import android.text.BidiFormatter
+import androidx.core.text.BidiFormatter
 import java.util.Locale
 import javax.inject.Inject
 
diff --git a/utility/src/main/java/org/oppia/android/util/parser/image/GlideImageLoader.kt b/utility/src/main/java/org/oppia/android/util/parser/image/GlideImageLoader.kt
index 0e190a13105..10e91bad48f 100644
--- a/utility/src/main/java/org/oppia/android/util/parser/image/GlideImageLoader.kt
+++ b/utility/src/main/java/org/oppia/android/util/parser/image/GlideImageLoader.kt
@@ -60,6 +60,7 @@ class GlideImageLoader @Inject constructor(
     target: ImageTarget<Drawable>,
     transformations: List<ImageTransformation>
   ) {
+    // TODO(#3887): Investigate why this has a native crash on KitKat & find a fix.
     glide
       .asDrawable()
       .load(imageDrawableResId)
diff --git a/version.bzl b/version.bzl
index c77ecc652bc..9ef6da3d3d2 100644
--- a/version.bzl
+++ b/version.bzl
@@ -4,4 +4,8 @@ Defines the latest version of the Oppia Android app.
 
 MAJOR_VERSION = 0
 MINOR_VERSION = 6
-VERSION_CODE = 8
+
+OPPIA_DEV_KITKAT_VERSION_CODE = 10
+OPPIA_DEV_VERSION_CODE = 11
+OPPIA_ALPHA_KITKAT_VERSION_CODE = 12
+OPPIA_ALPHA_VERSION_CODE = 13