diff --git a/.rubocop.yml b/.rubocop.yml
index 34ad98f94..13bf5fea8 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -17,13 +17,16 @@ AllCops:
 RedundantBlockCall:
   Enabled: false
 
+BlockLength:
+  Enabled: false
+
 # Avoid more than `Max` levels of nesting.
 BlockNesting:
   Max: 2
 
 # Indentation of when/else
 CaseIndentation:
-  IndentWhenRelativeTo: end
+  EnforcedStyle: end
   IndentOneStep: false
 
 ClassLength:
@@ -49,6 +52,10 @@ DotPosition:
 DoubleNegation:
   Enabled: false
 
+# Detects any duplication as issue including our conditional requires
+DuplicatedGem:
+  Enabled: false
+
 EmptyLinesAroundAccessModifier:
   Enabled: true
 
@@ -58,7 +65,10 @@ Encoding:
 
 # Align ends correctly
 EndAlignment:
-  AlignWith: variable
+  EnforcedStyleAlignWith: variable
+
+Style/FrozenStringLiteralComment:
+  Enabled: false
 
 # Enforce Ruby 1.8-compatible hash syntax
 HashSyntax:
@@ -77,6 +87,9 @@ MethodLength:
 MultilineOperationIndentation:
   EnforcedStyle: indented
 
+Style/NumericPredicate:
+  Enabled: false
+
 # Avoid long parameter lists
 ParameterLists:
   Max: 4
@@ -103,6 +116,9 @@ RegexpLiteral:
 RescueModifier:
   Enabled: false
 
+Style/SafeNavigation:
+  Enabled: false
+
 SignalException:
   EnforcedStyle: only_raise
 
@@ -110,6 +126,9 @@ SignalException:
 SpaceInsideHashLiteralBraces:
   EnforcedStyle: no_space
 
+Style/SymbolArray:
+  Enabled: false
+
 SymbolProc:
   Enabled: false
 
@@ -119,5 +138,8 @@ TrailingCommaInLiteral:
 TrailingCommaInArguments:
   Enabled: false
 
+YAMLLoad:
+  Enabled: false
+
 ZeroLengthPredicate:
   Enabled: false
diff --git a/.travis.yml b/.travis.yml
index 2890e151f..d911f7a4c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,16 +3,15 @@ env:
   global:
     - JRUBY_OPTS="$JRUBY_OPTS --debug"
   matrix:
-    - RAILS_VERSION="~> 4.0.0"
-    - RAILS_VERSION="~> 4.1.0"
     - RAILS_VERSION="~> 4.2.0"
-    - RAILS_VERSION="~> 5.0.0.beta1"
+    - RAILS_VERSION="~> 5.0.0"
+    - RAILS_VERSION="~> 5.1.0.rc1"
     - RAILS_VERSION="edge"
 rvm:
-  - 2.0.0
   - 2.1
-  - 2.2.5
-  - 2.3.1
+  - 2.2.6
+  - 2.3.3
+  - 2.4.1
   - jruby-9.0.5.0
   - jruby-head
   - rbx-2
@@ -27,6 +26,8 @@ matrix:
     - rvm: rbx-2
     - rvm: ruby-head
     - env: RAILS_VERSION="edge"
+    - rvm: jruby-9.0.5.0
+      env: RAILS_VERSION="~> 5.1.0.rc1"
   fast_finish: true
   # legacy testing
   # things still run and we don't have a good reason to break it
@@ -38,11 +39,17 @@ matrix:
       env: RAILS_VERSION="~> 3.1.0"
     - rvm: 2.1
       env: RAILS_VERSION="~> 3.2.0"
+    - rvm: 2.1
+      env: RAILS_VERSION="~> 4.0.0"
+    - rvm: 2.3.3
+      env: RAILS_VERSION="~> 4.1.0"
 
   exclude:
-    - rvm: 2.0.0
-      env: RAILS_VERSION="~> 5.0.0.beta1"
     - rvm: 2.1
-      env: RAILS_VERSION="~> 5.0.0.beta1"
+      env: RAILS_VERSION="~> 5.0.0"
+    - rvm: 2.1
+      env: RAILS_VERSION="~> 5.1.0.rc1"
+    - rvm: 2.1
+      env: RAILS_VERSION="edge"
 
 sudo: false
diff --git a/Gemfile b/Gemfile
index 9a781192f..593c62460 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,5 +1,7 @@
 source 'https://rubygems.org'
 
+rails_version = ENV['RAILS_VERSION'] || ''
+
 gem 'rake'
 
 platforms :ruby do
@@ -8,7 +10,13 @@ end
 
 platforms :jruby do
   gem 'jruby-openssl'
-  gem 'activerecord-jdbcsqlite3-adapter'
+  if rails_version == 'edge' || rails_version.match(/5\.\d+\.\d+/)
+    gem 'activerecord-jdbcsqlite3-adapter',
+        :git => 'https://github.com/jruby/activerecord-jdbc-adapter.git',
+        :branch => 'rails-5'
+  else
+    gem 'activerecord-jdbcsqlite3-adapter'
+  end
   gem 'mime-types', ['~> 2.6', '< 2.99']
 end
 
@@ -18,16 +26,16 @@ end
 
 group :test do
   if ENV['RAILS_VERSION'] == 'edge'
-    gem 'activerecord', :github => 'rails/rails'
     gem 'actionmailer', :github => 'rails/rails'
+    gem 'activerecord', :github => 'rails/rails'
   else
-    gem 'activerecord', (ENV['RAILS_VERSION'] || ['>= 3.0', '< 5.1'])
     gem 'actionmailer', (ENV['RAILS_VERSION'] || ['>= 3.0', '< 5.1'])
+    gem 'activerecord', (ENV['RAILS_VERSION'] || ['>= 3.0', '< 5.1'])
   end
 
   gem 'coveralls', :require => false
   gem 'rspec', '>= 3'
-  gem 'rubocop', '>= 0.25'
+  gem 'rubocop', '>= 0.25', '< 0.49'
   gem 'simplecov', '>= 0.9'
 end
 
diff --git a/README.md b/README.md
index d38ef3856..a6e4bfa7f 100644
--- a/README.md
+++ b/README.md
@@ -37,8 +37,7 @@ multitude of core tasks. Amongst those tasks are:
 
 Installation
 ============
-delayed_job 3.0.0 only supports Rails 3.0+. See the [2.0
-branch](https://github.com/collectiveidea/delayed_job/tree/v2.0) for Rails 2.
+delayed_job 3.0.0 only supports Rails 3.0+.
 
 delayed_job supports multiple backends for storing the job queue. [See the wiki
 for other backends](https://github.com/collectiveidea/delayed_job/wiki/Backends).
@@ -220,6 +219,12 @@ Configured queue priorities can be overriden by passing priority to the delay me
 object.delay(:queue => 'high_priority', priority: 0).method
 ```
 
+You can start processes to only work certain queues with the `queue` and `queues`
+options defined below. Processes started without specifying a queue will run jobs
+from **any** queue. To effectively have a process that runs jobs where a queue is not
+specified, set a default queue name with `Delayed::Worker.default_queue_name` and 
+have the processes run that queue.
+
 Running Jobs
 ============
 `script/delayed_job` can be used to manage a background process which will
diff --git a/lib/delayed/backend/base.rb b/lib/delayed/backend/base.rb
index cd885b9b9..4f18fb39d 100644
--- a/lib/delayed/backend/base.rb
+++ b/lib/delayed/backend/base.rb
@@ -30,16 +30,13 @@ def reserve(worker, max_run_time = Worker.max_run_time)
         end
 
         # Allow the backend to attempt recovery from reserve errors
-        def recover_from(_error)
-        end
+        def recover_from(_error); end
 
         # Hook method that is called before a new worker is forked
-        def before_fork
-        end
+        def before_fork; end
 
         # Hook method that is called after a new worker is forked
-        def after_fork
-        end
+        def after_fork; end
 
         def work_off(num = 100)
           warn '[DEPRECATION] `Delayed::Job.work_off` is deprecated. Use `Delayed::Worker.new.work_off instead.'
@@ -101,7 +98,7 @@ def unlock
       def hook(name, *args)
         if payload_object.respond_to?(name)
           method = payload_object.method(name)
-          method.arity == 0 ? method.call : method.call(self, *args)
+          method.arity.zero? ? method.call : method.call(self, *args)
         end
       rescue DeserializationError # rubocop:disable HandleExceptions
       end
diff --git a/lib/delayed/backend/job_preparer.rb b/lib/delayed/backend/job_preparer.rb
index 52d0d32c8..f545eda0e 100644
--- a/lib/delayed/backend/job_preparer.rb
+++ b/lib/delayed/backend/job_preparer.rb
@@ -4,7 +4,7 @@ class JobPreparer
       attr_reader :options, :args
 
       def initialize(*args)
-        @options = args.extract_options!
+        @options = args.extract_options!.dup
         @args = args
       end
 
@@ -42,9 +42,11 @@ def handle_deprecation
           options[:run_at]   = args[1]
         end
 
+        # rubocop:disable GuardClause
         unless options[:payload_object].respond_to?(:perform)
           raise ArgumentError, 'Cannot enqueue items which do not respond to perform'
         end
+        # rubocop:enabled GuardClause
       end
     end
   end
diff --git a/lib/delayed/backend/shared_spec.rb b/lib/delayed/backend/shared_spec.rb
index df465a9a2..771e0cd9c 100644
--- a/lib/delayed/backend/shared_spec.rb
+++ b/lib/delayed/backend/shared_spec.rb
@@ -113,6 +113,12 @@ def create_job(opts = {})
         job = described_class.enqueue M::ModuleJob.new
         expect { job.invoke_job }.to change { M::ModuleJob.runs }.from(0).to(1)
       end
+
+      it 'does not mutate the options hash' do
+        options = {:priority => 1}
+        described_class.enqueue SimpleJob.new, options
+        expect(options).to eq(:priority => 1)
+      end
     end
 
     context 'with delay_jobs = false' do
diff --git a/lib/delayed/command.rb b/lib/delayed/command.rb
index 58a2d91c9..281078242 100644
--- a/lib/delayed/command.rb
+++ b/lib/delayed/command.rb
@@ -91,11 +91,13 @@ def daemonize # rubocop:disable PerceivedComplexity
       if worker_pools
         setup_pools
       elsif @options[:identifier]
+        # rubocop:disable GuardClause
         if worker_count > 1
           raise ArgumentError, 'Cannot specify both --number-of-workers and --identifier'
         else
           run_process("delayed_job.#{@options[:identifier]}", @options)
         end
+        # rubocop:enable GuardClause
       else
         worker_count.times do |worker_index|
           process_name = worker_count == 1 ? 'delayed_job' : "delayed_job.#{worker_index}"
diff --git a/lib/delayed/exceptions.rb b/lib/delayed/exceptions.rb
index 542361dea..11f132276 100644
--- a/lib/delayed/exceptions.rb
+++ b/lib/delayed/exceptions.rb
@@ -8,5 +8,5 @@ def message
     end
   end
 
-  class FatalBackendError < Exception; end
+  class FatalBackendError < RuntimeError; end
 end
diff --git a/lib/delayed/lifecycle.rb b/lib/delayed/lifecycle.rb
index 63ab1b14f..57dbf98a9 100644
--- a/lib/delayed/lifecycle.rb
+++ b/lib/delayed/lifecycle.rb
@@ -1,5 +1,5 @@
 module Delayed
-  class InvalidCallback < Exception; end
+  class InvalidCallback < RuntimeError; end
 
   class Lifecycle
     EVENTS = {
diff --git a/lib/delayed/message_sending.rb b/lib/delayed/message_sending.rb
index 5bf8b6dad..a2808fd39 100644
--- a/lib/delayed/message_sending.rb
+++ b/lib/delayed/message_sending.rb
@@ -6,9 +6,11 @@ def initialize(payload_class, target, options)
       @options = options
     end
 
+    # rubocop:disable MethodMissing
     def method_missing(method, *args)
       Job.enqueue({:payload_object => @payload_class.new(@target, method.to_sym, args)}.merge(@options))
     end
+    # rubocop:enable MethodMissing
   end
 
   module MessageSending
@@ -26,36 +28,36 @@ def send_at(time, method, *args)
       warn '[DEPRECATION] `object.send_at(time, :method)` is deprecated. Use `object.delay(:run_at => time).method'
       __delay__(:run_at => time).__send__(method, *args)
     end
+  end
 
-    module ClassMethods
-      def handle_asynchronously(method, opts = {}) # rubocop:disable PerceivedComplexity
-        aliased_method = method.to_s.sub(/([?!=])$/, '')
-        punctuation = $1 # rubocop:disable PerlBackrefs
-        with_method = "#{aliased_method}_with_delay#{punctuation}"
-        without_method = "#{aliased_method}_without_delay#{punctuation}"
-        define_method(with_method) do |*args|
-          curr_opts = opts.clone
-          curr_opts.each_key do |key|
-            next unless (val = curr_opts[key]).is_a?(Proc)
-            curr_opts[key] = if val.arity == 1
-              val.call(self)
-            else
-              val.call
-            end
+  module MessageSendingClassMethods
+    def handle_asynchronously(method, opts = {}) # rubocop:disable PerceivedComplexity
+      aliased_method = method.to_s.sub(/([?!=])$/, '')
+      punctuation = $1 # rubocop:disable PerlBackrefs
+      with_method = "#{aliased_method}_with_delay#{punctuation}"
+      without_method = "#{aliased_method}_without_delay#{punctuation}"
+      define_method(with_method) do |*args|
+        curr_opts = opts.clone
+        curr_opts.each_key do |key|
+          next unless (val = curr_opts[key]).is_a?(Proc)
+          curr_opts[key] = if val.arity == 1
+            val.call(self)
+          else
+            val.call
           end
-          delay(curr_opts).__send__(without_method, *args)
         end
+        delay(curr_opts).__send__(without_method, *args)
+      end
 
-        alias_method without_method, method
-        alias_method method, with_method
+      alias_method without_method, method
+      alias_method method, with_method
 
-        if public_method_defined?(without_method)
-          public method
-        elsif protected_method_defined?(without_method)
-          protected method
-        elsif private_method_defined?(without_method)
-          private method
-        end
+      if public_method_defined?(without_method)
+        public method
+      elsif protected_method_defined?(without_method)
+        protected method
+      elsif private_method_defined?(without_method)
+        private method
       end
     end
   end
diff --git a/lib/delayed/performable_method.rb b/lib/delayed/performable_method.rb
index 0bd1fea49..96a28b056 100644
--- a/lib/delayed/performable_method.rb
+++ b/lib/delayed/performable_method.rb
@@ -30,9 +30,11 @@ def method(sym)
       object.method(sym)
     end
 
+    # rubocop:disable MethodMissing
     def method_missing(symbol, *args)
       object.send(symbol, *args)
     end
+    # rubocop:enable MethodMissing
 
     def respond_to?(symbol, include_private = false)
       super || object.respond_to?(symbol, include_private)
diff --git a/lib/delayed/psych_ext.rb b/lib/delayed/psych_ext.rb
index 2c535237e..5b12df0c9 100644
--- a/lib/delayed/psych_ext.rb
+++ b/lib/delayed/psych_ext.rb
@@ -37,7 +37,7 @@ def visit_Psych_Nodes_Mapping(object) # rubocop:disable CyclomaticComplexity, Me
             klass = result.class
             id = result[klass.primary_key]
             begin
-              klass.find(id)
+              klass.unscoped.find(id)
             rescue ActiveRecord::RecordNotFound => error # rubocop:disable BlockNesting
               raise Delayed::DeserializationError, "ActiveRecord::RecordNotFound, class: #{klass}, primary key: #{id} (#{error.message})"
             end
diff --git a/lib/delayed/worker.rb b/lib/delayed/worker.rb
index 2c3081f05..c02f0523e 100644
--- a/lib/delayed/worker.rb
+++ b/lib/delayed/worker.rb
@@ -116,7 +116,7 @@ def self.setup_lifecycle
     end
 
     def self.reload_app?
-      defined?(ActionDispatch::Reloader) && Rails.application.config.cache_classes == false
+      Rails.application.reloaders.any?(&:updated?) && Rails.application.config.cache_classes == false
     end
 
     def self.delay_job?(job)
@@ -233,6 +233,8 @@ def run(job)
       job_say job, format('COMPLETED after %.4f', runtime)
       return true # did work
     rescue DeserializationError => error
+      job_say job, "FAILED permanently with #{error.class.name}: #{error.message}", 'error'
+
       job.error = error
       failed(job)
     rescue Exception => error # rubocop:disable RescueException
@@ -268,7 +270,7 @@ def failed(job)
     end
 
     def job_say(job, text, level = default_log_level)
-      text = "Job #{job.name} (id=#{job.id}) #{text}"
+      text = "Job #{job.name} (id=#{job.id})#{say_queue(job.queue)} #{text}"
       say text, level
     end
 
@@ -293,6 +295,10 @@ def max_run_time(job)
 
   protected
 
+    def say_queue(queue)
+      " (queue=#{queue})" if queue
+    end
+
     def handle_failed_job(job, error)
       job.error = error
       job_say job, "FAILED (#{job.attempts} prior attempts) with #{error.class.name}: #{error.message}", 'error'
@@ -320,8 +326,12 @@ def reserve_job
 
     def reload!
       return unless self.class.reload_app?
-      ActionDispatch::Reloader.cleanup!
-      ActionDispatch::Reloader.prepare!
+      if defined?(ActiveSupport::Reloader)
+        Rails.application.reloader.reload!
+      else
+        ActionDispatch::Reloader.cleanup!
+        ActionDispatch::Reloader.prepare!
+      end
     end
   end
 end
diff --git a/lib/delayed_job.rb b/lib/delayed_job.rb
index 808831595..439dd8587 100644
--- a/lib/delayed_job.rb
+++ b/lib/delayed_job.rb
@@ -1,3 +1,4 @@
+require 'active_support'
 require 'delayed/compatibility'
 require 'delayed/exceptions'
 require 'delayed/message_sending'
@@ -19,4 +20,4 @@
 require 'delayed/railtie' if defined?(Rails::Railtie)
 
 Object.send(:include, Delayed::MessageSending)
-Module.send(:include, Delayed::MessageSending::ClassMethods)
+Module.send(:include, Delayed::MessageSendingClassMethods)
diff --git a/lib/generators/delayed_job/delayed_job_generator.rb b/lib/generators/delayed_job/delayed_job_generator.rb
index cba43c161..60b473055 100644
--- a/lib/generators/delayed_job/delayed_job_generator.rb
+++ b/lib/generators/delayed_job/delayed_job_generator.rb
@@ -6,6 +6,6 @@ class DelayedJobGenerator < Rails::Generators::Base
 
   def create_executable_file
     template 'script', "#{Delayed::Compatibility.executable_prefix}/delayed_job"
-    chmod "#{Delayed::Compatibility.executable_prefix}/delayed_job", 0755
+    chmod "#{Delayed::Compatibility.executable_prefix}/delayed_job", 0o755
   end
 end
diff --git a/spec/autoloaded/clazz.rb b/spec/autoloaded/clazz.rb
index 5c5756d8b..daa9e9213 100644
--- a/spec/autoloaded/clazz.rb
+++ b/spec/autoloaded/clazz.rb
@@ -1,7 +1,6 @@
 # Make sure this file does not get required manually
 module Autoloaded
   class Clazz
-    def perform
-    end
+    def perform; end
   end
 end
diff --git a/spec/autoloaded/instance_clazz.rb b/spec/autoloaded/instance_clazz.rb
index c6e4d4a30..1e72c2bff 100644
--- a/spec/autoloaded/instance_clazz.rb
+++ b/spec/autoloaded/instance_clazz.rb
@@ -1,6 +1,5 @@
 module Autoloaded
   class InstanceClazz
-    def perform
-    end
+    def perform; end
   end
 end
diff --git a/spec/autoloaded/instance_struct.rb b/spec/autoloaded/instance_struct.rb
index 68a9b9485..80d3daffc 100644
--- a/spec/autoloaded/instance_struct.rb
+++ b/spec/autoloaded/instance_struct.rb
@@ -1,7 +1,6 @@
 module Autoloaded
   InstanceStruct = ::Struct.new(nil)
   class InstanceStruct
-    def perform
-    end
+    def perform; end
   end
 end
diff --git a/spec/autoloaded/struct.rb b/spec/autoloaded/struct.rb
index 4e20bd7b5..97cba2cc9 100644
--- a/spec/autoloaded/struct.rb
+++ b/spec/autoloaded/struct.rb
@@ -2,7 +2,6 @@
 module Autoloaded
   Struct = ::Struct.new(nil)
   class Struct
-    def perform
-    end
+    def perform; end
   end
 end
diff --git a/spec/message_sending_spec.rb b/spec/message_sending_spec.rb
index 7b4b98d17..ca58edcc1 100644
--- a/spec/message_sending_spec.rb
+++ b/spec/message_sending_spec.rb
@@ -1,6 +1,11 @@
 require 'helper'
 
 describe Delayed::MessageSending do
+  it 'does not include ClassMethods along with MessageSending' do
+    expect { ClassMethods }.to raise_error(NameError)
+    expect(defined?(String::ClassMethods)).to eq(nil)
+  end
+
   describe 'handle_asynchronously' do
     class Story
       def tell!(_arg); end
@@ -19,7 +24,7 @@ def tell!(_arg); end
         expect(job.payload_object.class).to eq(Delayed::PerformableMethod)
         expect(job.payload_object.method_name).to eq(:tell_without_delay!)
         expect(job.payload_object.args).to eq([1])
-      end.to change { Delayed::Job.count }
+      end.to(change { Delayed::Job.count })
     end
 
     describe 'with options' do
@@ -42,8 +47,7 @@ def tell; end
       describe 'using a proc with parameters' do
         class Yarn
           attr_accessor :importance
-          def spin
-          end
+          def spin; end
           handle_asynchronously :spin, :priority => proc { |y| y.importance }
         end
 
@@ -107,7 +111,7 @@ def tell
         expect do
           fairy_tail.delay.tell
         end.to change(fairy_tail, :happy_ending).from(nil).to(true)
-      end.not_to change { Delayed::Job.count }
+      end.not_to(change { Delayed::Job.count })
     end
 
     it 'does delay the job when delay_jobs is true' do
@@ -137,7 +141,7 @@ def tell
         expect do
           fairy_tail.delay.tell
         end.to change(fairy_tail, :happy_ending).from(nil).to(true)
-      end.not_to change { Delayed::Job.count }
+      end.not_to(change { Delayed::Job.count })
     end
   end
 end
diff --git a/spec/performable_method_spec.rb b/spec/performable_method_spec.rb
index 751340618..a4d700322 100644
--- a/spec/performable_method_spec.rb
+++ b/spec/performable_method_spec.rb
@@ -30,8 +30,7 @@
 
   it 'does not raise NoMethodError if target method is private' do
     clazz = Class.new do
-      def private_method
-      end
+      def private_method; end
       private :private_method
     end
     expect { Delayed::PerformableMethod.new(clazz.new, :private_method, []) }.not_to raise_error
diff --git a/spec/worker_spec.rb b/spec/worker_spec.rb
index 2f0054234..1ce08ce99 100644
--- a/spec/worker_spec.rb
+++ b/spec/worker_spec.rb
@@ -24,15 +24,23 @@
   describe 'job_say' do
     before do
       @worker = Delayed::Worker.new
-      @job = double('job', :id => 123, :name => 'ExampleJob')
+      @job = double('job', :id => 123, :name => 'ExampleJob', :queue => nil)
     end
 
     it 'logs with job name and id' do
+      expect(@job).to receive(:queue)
       expect(@worker).to receive(:say).
         with('Job ExampleJob (id=123) message', Delayed::Worker.default_log_level)
       @worker.job_say(@job, 'message')
     end
 
+    it 'logs with job name, queue and id' do
+      expect(@job).to receive(:queue).and_return('test')
+      expect(@worker).to receive(:say).
+        with('Job ExampleJob (id=123) (queue=test) message', Delayed::Worker.default_log_level)
+      @worker.job_say(@job, 'message')
+    end
+
     it 'has a configurable default log level' do
       Delayed::Worker.default_log_level = 'error'