diff --git a/CMakeLists.txt b/CMakeLists.txt
index 81a36e8..b35cde2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -44,7 +44,8 @@ add_compile_options(-std=c++14
                     -Wuninitialized
                     -Wconversion
                     -Wno-missing-field-initializers
-                    -Wno-unused-parameter)
+                    -Wno-unused-parameter
+                    -Wno-gnu-zero-variadic-macro-arguments)
 
 # Use shared libraries in this project
 set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -stdlib=libc++")
diff --git a/msi_http_send_file/msi_http_send_file.cpp b/msi_http_send_file/msi_http_send_file.cpp
index b6ca098..3d0d2f2 100644
--- a/msi_http_send_file/msi_http_send_file.cpp
+++ b/msi_http_send_file/msi_http_send_file.cpp
@@ -104,8 +104,7 @@ class irodsCurl {
         dataObjInp_t file;
         openedDataObjInp_t openedFile;
         bytesBuf_t bytesBuf;
-
-        size_t bytesRead;
+        int bytesRead;
 
         // Make sure we have something to read from
         if (!readData) {
@@ -140,16 +139,15 @@ class irodsCurl {
         openedFile.l1descInx = readData->desc;
         openedFile.len = bytesBuf.len;
 
-        // bytesRead = 0;
-        //TODO: At Paul: during compilation warning: implicit conversion changes signedness: 'int' to 'size_t' (aka 'unsigned long')
+        // Read iRODS object
         bytesRead = rsDataObjRead(readData->rsComm, &openedFile, &bytesBuf);
-        //TODO: At Paul: during compilation warning: comparison of unsigned expression < 0 is always false
+
         if (bytesRead < 0) {
             rodsLog(LOG_ERROR, "irods_http_send_file: Problem reading iRODS object. Status =  %d", bytesRead);
             return CURL_READFUNC_ABORT;
         }
 
-        return (bytesRead);
+        return (size_t) bytesRead;
     }
 
 }; 	// class irodsCurl
@@ -161,8 +159,6 @@ extern "C" {
 // 1. Write a standard issue microservice
     int irods_http_send_file( msParam_t* url, msParam_t* src_obj, ruleExecInfo_t* rei ) {
         dataObjInp_t dataObjInp, *myDataObjInp;
-        //TODO: At Paul: during compilation "warning: unused variable 'myUrl'"
-        char *myUrl;
 
         // Sanity checks
         if ( !rei || !rei->rsComm ) {
diff --git a/msi_json_arrayops/libmsi_json_arrayops.cpp b/msi_json_arrayops/libmsi_json_arrayops.cpp
index 6fac74b..635d785 100644
--- a/msi_json_arrayops/libmsi_json_arrayops.cpp
+++ b/msi_json_arrayops/libmsi_json_arrayops.cpp
@@ -22,7 +22,7 @@ extern "C" {
         const char *inJsonStr = parseMspForStr( json_str );
         const char *inVal = parseMspForStr( val );
         const char *inOps = parseMspForStr( ops );
-        const int inIdx = parseMspForPosInt( sizeOrIndex );
+        int inIdx = parseMspForPosInt( sizeOrIndex );
 
         if( ! inJsonStr ) {
             cout << "msi_json_arrayops - invalid inJsonStr" << endl;
@@ -69,9 +69,9 @@ extern "C" {
         }
 
         // find if jval is already presented in array
-        size_t i_match = outSizeOrIndex;
+        int i_match = outSizeOrIndex;
         for( int i=0; i < outSizeOrIndex; i++ ) {
-            json_t *ov = json_array_get(root, i);
+            json_t *ov = json_array_get(root, (size_t) i);
             if ( json_equal(ov, jval) ) { i_match = i; break; }
         }
 
@@ -85,7 +85,7 @@ extern "C" {
 
             if ( i_match < outSizeOrIndex ) {
                 if ( strOps == "rm" ) {
-                    json_array_remove(root, i_match);
+                    json_array_remove(root, (size_t) i_match);
                     outSizeOrIndex = (int) json_array_size(root);
                 } else {
                     outSizeOrIndex = i_match;
@@ -96,7 +96,7 @@ extern "C" {
         } else if ( strOps == "size" ) {
             outSizeOrIndex = (int) json_array_size(root);
         } else if ( strOps == "get" ) {
-            json_t *elem = json_array_get(root, inIdx);
+            json_t *elem = json_array_get(root, (size_t) inIdx);
 
             // Updated our rule with added functionality from Utrecht University
             /* output a string directly, but encode other json types using json_dumps with JSON_ENCODE_ANY set */
diff --git a/msi_json_objops/libmsi_json_objops.cpp b/msi_json_objops/libmsi_json_objops.cpp
index 91a4031..8973fb5 100644
--- a/msi_json_objops/libmsi_json_objops.cpp
+++ b/msi_json_objops/libmsi_json_objops.cpp
@@ -104,7 +104,7 @@ extern "C" {
                 if ( data ) {
                     if ( json_is_array( data ) ) {
                         size_t i_match = json_array_size(data);
-                        for( int i=0; i<json_array_size(data); i++ ) {
+                        for( size_t i=0; i<json_array_size(data); i++ ) {
                             json_t *ov = json_array_get(data, i);
                             if ( json_equal(ov, jval) ) { i_match = i; break; }
                         }
diff --git a/msiput_dataobj_or_coll/libmsiput_dataobj_or_coll.cpp b/msiput_dataobj_or_coll/libmsiput_dataobj_or_coll.cpp
index 73df5bd..dc3a6e0 100644
--- a/msiput_dataobj_or_coll/libmsiput_dataobj_or_coll.cpp
+++ b/msiput_dataobj_or_coll/libmsiput_dataobj_or_coll.cpp
@@ -1,12 +1,5 @@
-// 2018-08-07 Ported this microservice to iRODS 4.2.3
-// Based my changes here on a diff between these two versions on irods/contrib:
-// 4.1 https://github.com/irods/contrib/blob/4-1-stable/microservices/landing_zone_microservices/msiput_dataobj_or_coll/libmsiput_dataobj_or_coll.cpp
-// 4.2 https://github.com/irods/contrib/blob/e31f055dee5e3e8ca76b2ccd6011f684dc2f130c/microservices/landing_zone_microservices/msiput_dataobj_or_coll/libmsiput_dataobj_or_coll.cpp
-
-//#include "reFuncDefs.h"
 #include "irods_ms_plugin.hpp"
 #include "objInfo.h"
-#include "reDataObjOpr.hpp"
 #include "collCreate.h"
 #include "dataObjPut.h"
 #include "collection.hpp"
@@ -25,7 +18,6 @@ void strip_trailing_slash(
     std::string& _path ) {
     if( *_path.rbegin() == '/' )
         _path = _path.substr( 0, _path.size()-1 );
-
 }
 
 
@@ -215,7 +207,7 @@ irods::error put_all_the_files(
 
 // =-=-=-=-=-=-=-
 // 1. Write a standard issue microservice
-int msiput_dataobj_or_coll(
+long long msiput_dataobj_or_coll(
     msParam_t* _path,
     msParam_t* _resc,
     msParam_t* _opts,
@@ -310,7 +302,7 @@ int msiput_dataobj_or_coll(
     if (!ret.ok()) {
         addRErrorMsg(
                 &rei->rsComm->rError,
-                ret.code(),
+                (int) ret.code(),
                 ret.result().c_str());
     }