diff --git a/.travis.yml b/.travis.yml
index 47d00e916..0836d2053 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,12 +1,26 @@
 rvm:
   - 2.1
-  - 2.2
+  - 2.2.2
 
 script: "bundle exec rake clean spec cucumber"
 
 gemfile:
-  - gemfiles/4.2.awsv2.1.gemfile
   - gemfiles/4.2.awsv2.0.gemfile
+  - gemfiles/4.2.awsv2.1.gemfile
+  - gemfiles/5.0.awsv2.0.gemfile
+  - gemfiles/5.0.awsv2.1.gemfile
+
+matrix:
+  fast_finish: true
+  exclude:
+    - gemfile: gemfiles/5.0.awsv2.0.gemfile
+      rvm: 2.0
+    - gemfile: gemfiles/5.0.awsv2.1.gemfile
+      rvm: 2.0
+    - gemfile: gemfiles/5.0.awsv2.0.gemfile
+      rvm: 2.1
+    - gemfile: gemfiles/5.0.awsv2.1.gemfile
+      rvm: 2.1
 
 sudo: false
 cache: bundler
diff --git a/Appraisals b/Appraisals
index 0570b5899..a3172e6d1 100644
--- a/Appraisals
+++ b/Appraisals
@@ -1,3 +1,8 @@
+appraise "4.2.awsv2.0" do
+  gem "rails", "~> 4.2.0"
+  gem "aws-sdk", "~> 2.0.0"
+end
+
 appraise "4.2.awsv2.1" do
   gem "rails", "~> 4.2.0"
   gem "aws-sdk", "~> 2.1.0"
@@ -7,11 +12,16 @@ appraise "4.2.awsv2.1" do
   end
 end
 
-appraise "4.2.awsv2.0" do
-  gem "rails", "~> 4.2.0"
+appraise "5.0.awsv2.0" do
+  gem "rails", "5.0.0.beta3"
   gem "aws-sdk", "~> 2.0.0"
 
   group :development, :test do
     gem 'mime-types', '>= 1.16', '< 4'
   end
 end
+
+appraise "5.0.awsv2.1" do
+  gem "rails", "5.0.0.beta3"
+  gem "aws-sdk", "~> 2.1.0"
+end
diff --git a/README.md b/README.md
index d66b6f64f..4a6b67186 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,13 @@
 Paperclip
 =========
 
+## Documentation valid for `master` branch
+
+Please check the documentation for the paperclip version you are using:
+https://github.com/thoughtbot/paperclip/releases
+
+---
+
 [![Build Status](https://secure.travis-ci.org/thoughtbot/paperclip.svg?branch=master)](http://travis-ci.org/thoughtbot/paperclip)
 [![Dependency Status](https://gemnasium.com/thoughtbot/paperclip.svg?travis)](https://gemnasium.com/thoughtbot/paperclip)
 [![Code Climate](https://codeclimate.com/github/thoughtbot/paperclip.svg)](https://codeclimate.com/github/thoughtbot/paperclip)
@@ -71,9 +78,8 @@ Requirements
 
 ### Ruby and Rails
 
-Paperclip now requires Ruby version **>= 2.0.0** and Rails version **3.2, >= 4.1** (Only if you're going to use Paperclip with Ruby on Rails.)
-
-If you're still on Ruby 1.8.7 or Ruby on Rails 2.3.x, you can still use Paperclip 2.7.x with your project. Also, everything in this README might not apply to your version of Paperclip, and you should read [the README for version 2.7](http://www.rubydoc.info/gems/paperclip/2.7.0) instead.
+Paperclip now requires Ruby version **>= 2.1** and Rails version **>= 4.2**
+(only if you're going to use Paperclip with Ruby on Rails.)
 
 ### Image Processor
 
@@ -100,7 +106,7 @@ to install GhostScript. On Mac OS X, you can also install that using Homebrew:
 
     brew install gs
 
-If you're on Ubuntu (or any Debian base Linux distribution), you'll want to run
+If you are on Ubuntu (or any Debian base Linux distribution), you'll want to run
 the following with apt-get:
 
     sudo apt-get install imagemagick -y
@@ -153,7 +159,7 @@ Paperclip is distributed as a gem, which is how it should be used in your app.
 Include the gem in your Gemfile:
 
 ```ruby
-gem "paperclip", "~> 4.3"
+gem "paperclip", "~> 5.0"
 ```
 
 Or, if you want to get the latest, you can get master from the main paperclip repository:
diff --git a/gemfiles/4.2.awsv2.0.gemfile b/gemfiles/4.2.awsv2.0.gemfile
index ef705dfd6..83ffed5d9 100644
--- a/gemfiles/4.2.awsv2.0.gemfile
+++ b/gemfiles/4.2.awsv2.0.gemfile
@@ -2,16 +2,16 @@
 
 source "https://rubygems.org"
 
-gem "sqlite3", "~> 1.3.8", platforms: :ruby
+gem "sqlite3", "~> 1.3.8", :platforms => :ruby
 gem "pry"
 gem "rails", "~> 4.2.0"
 gem "aws-sdk", "~> 2.0.0"
 
 group :development, :test do
   gem "activerecord-import"
-  gem "mime-types", ">= 1.16", "< 4"
+  gem "mime-types"
   gem "builder"
   gem "rubocop", :require => false
 end
 
-gemspec path: "../"
+gemspec :path => "../"
diff --git a/gemfiles/4.2.awsv2.1.gemfile b/gemfiles/4.2.awsv2.1.gemfile
index 9b52119cf..b6b17d272 100644
--- a/gemfiles/4.2.awsv2.1.gemfile
+++ b/gemfiles/4.2.awsv2.1.gemfile
@@ -2,7 +2,7 @@
 
 source "https://rubygems.org"
 
-gem "sqlite3", "~> 1.3.8", platforms: :ruby
+gem "sqlite3", "~> 1.3.8", :platforms => :ruby
 gem "pry"
 gem "rails", "~> 4.2.0"
 gem "aws-sdk", "~> 2.1.0"
@@ -14,4 +14,4 @@ group :development, :test do
   gem "rubocop", :require => false
 end
 
-gemspec path: "../"
+gemspec :path => "../"
diff --git a/gemfiles/4.2.awsv2.gemfile b/gemfiles/4.2.awsv2.gemfile
new file mode 100644
index 000000000..3ac60abcd
--- /dev/null
+++ b/gemfiles/4.2.awsv2.gemfile
@@ -0,0 +1,20 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "sqlite3", "~> 1.3.8", :platforms => :ruby
+gem "jruby-openssl", :platforms => :jruby
+gem "activerecord-jdbcsqlite3-adapter", :platforms => :jruby
+gem "rubysl", :platforms => :rbx
+gem "racc", :platforms => :rbx
+gem "pry"
+gem "rails", "~> 4.2.0"
+gem "aws-sdk", "~> 2.0"
+
+group :development, :test do
+  gem "mime-types", "~> 1.16"
+  gem "builder"
+  gem "rubocop", :require => false
+end
+
+gemspec :path => "../"
diff --git a/gemfiles/5.0.awsv2.0.gemfile b/gemfiles/5.0.awsv2.0.gemfile
new file mode 100644
index 000000000..4fd23dc14
--- /dev/null
+++ b/gemfiles/5.0.awsv2.0.gemfile
@@ -0,0 +1,17 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "sqlite3", "~> 1.3.8", :platforms => :ruby
+gem "pry"
+gem "rails", "5.0.0.beta3"
+gem "aws-sdk", "~> 2.0.0"
+
+group :development, :test do
+  gem "activerecord-import"
+  gem "mime-types", ">= 1.16", "< 4"
+  gem "builder"
+  gem "rubocop", :require => false
+end
+
+gemspec :path => "../"
diff --git a/gemfiles/5.0.awsv2.1.gemfile b/gemfiles/5.0.awsv2.1.gemfile
new file mode 100644
index 000000000..75049f705
--- /dev/null
+++ b/gemfiles/5.0.awsv2.1.gemfile
@@ -0,0 +1,17 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "sqlite3", "~> 1.3.8", :platforms => :ruby
+gem "pry"
+gem "rails", "5.0.0.beta3"
+gem "aws-sdk", "~> 2.1.0"
+
+group :development, :test do
+  gem "activerecord-import"
+  gem "mime-types"
+  gem "builder"
+  gem "rubocop", :require => false
+end
+
+gemspec :path => "../"
diff --git a/gemfiles/5.0.awsv2.gemfile b/gemfiles/5.0.awsv2.gemfile
new file mode 100644
index 000000000..29c4b6020
--- /dev/null
+++ b/gemfiles/5.0.awsv2.gemfile
@@ -0,0 +1,25 @@
+# This file was generated by Appraisal
+
+source "https://rubygems.org"
+
+gem "sqlite3", "~> 1.3.8", :platforms => :ruby
+gem "jruby-openssl", :platforms => :jruby
+gem "activerecord-jdbcsqlite3-adapter", :platforms => :jruby
+gem "rubysl", :platforms => :rbx
+gem "racc", :platforms => :rbx
+gem "pry"
+gem "rails", :github => "rails/rails"
+gem "sprockets-rails", :github => "rails/sprockets-rails"
+gem "sprockets", :github => "rails/sprockets"
+gem "sass-rails", :github => "rails/sass-rails"
+gem "arel", :github => "rails/arel"
+gem "rack", :github => "rack/rack"
+gem "aws-sdk", "~> 2.0"
+
+group :development, :test do
+  gem "mime-types", "~> 1.16"
+  gem "builder"
+  gem "rubocop", :require => false
+end
+
+gemspec :path => "../"
diff --git a/lib/paperclip/attachment.rb b/lib/paperclip/attachment.rb
index ae8bb27ea..d3e81a0cd 100644
--- a/lib/paperclip/attachment.rb
+++ b/lib/paperclip/attachment.rb
@@ -501,7 +501,7 @@ def post_process(*style_args) #:nodoc:
 
       instance.run_paperclip_callbacks(:post_process) do
         instance.run_paperclip_callbacks(:"#{name}_post_process") do
-          unless @options[:check_validity_before_processing] && instance.errors.any?
+          if !@options[:check_validity_before_processing] || !instance.errors.any?
             post_process_styles(*style_args)
           end
         end
diff --git a/lib/paperclip/callbacks.rb b/lib/paperclip/callbacks.rb
index e3525f6d0..53a436857 100644
--- a/lib/paperclip/callbacks.rb
+++ b/lib/paperclip/callbacks.rb
@@ -7,7 +7,7 @@ def self.included(base)
 
     module Defining
       def define_paperclip_callbacks(*callbacks)
-        define_callbacks(*[callbacks, {:terminator => callback_terminator}].flatten)
+        define_callbacks(*[callbacks, { terminator: hasta_la_vista_baby }].flatten)
         callbacks.each do |callback|
           eval <<-end_callbacks
             def before_#{callback}(*args, &blk)
@@ -22,11 +22,13 @@ def after_#{callback}(*args, &blk)
 
       private
 
-      def callback_terminator
-        if ::ActiveSupport::VERSION::STRING >= '4.1'
-          lambda { |target, result| result == false }
-        else
-          'result == false'
+      def hasta_la_vista_baby
+        lambda do |_, result|
+          if result.respond_to?(:call)
+            result.call == false
+          else
+            result == false
+          end
         end
       end
     end
diff --git a/spec/paperclip/validators_spec.rb b/spec/paperclip/validators_spec.rb
index 398948d83..93a57e26b 100644
--- a/spec/paperclip/validators_spec.rb
+++ b/spec/paperclip/validators_spec.rb
@@ -64,12 +64,11 @@
       assert_raises(RuntimeError){ dummy.valid? }
     end
 
-    it 'allows you to attach a file that does not violates these validations' do
+    it 'allows you to attach a file that does not violate these validations' do
       dummy = Dummy.new(avatar: File.new(fixture_file('rotated.jpg')))
-      expect(dummy.errors.keys).to match_array []
+      expect(dummy.errors.full_messages).to be_empty
       assert dummy.valid?
     end
-
   end
 
   context "using the helper with a conditional" do
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 036770123..92e7f431f 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -36,6 +36,7 @@
   config.include Assertions
   config.include ModelReconstruction
   config.include TestData
+  config.include Reporting
   config.extend VersionHelper
   config.mock_framework = :mocha
   config.before(:all) do
diff --git a/spec/support/model_reconstruction.rb b/spec/support/model_reconstruction.rb
index 0caac56cc..a2e9b4461 100644
--- a/spec/support/model_reconstruction.rb
+++ b/spec/support/model_reconstruction.rb
@@ -10,7 +10,15 @@ def reset_class class_name
 
     klass.reset_column_information
     klass.connection_pool.clear_table_cache!(klass.table_name) if klass.connection_pool.respond_to?(:clear_table_cache!)
-    klass.connection.schema_cache.clear_table_cache!(klass.table_name) if klass.connection.respond_to?(:schema_cache)
+
+    if klass.connection.respond_to?(:schema_cache)
+      if ActiveRecord::VERSION::STRING >= "5.0"
+        klass.connection.schema_cache.clear_data_source_cache!(klass.table_name)
+      else
+        klass.connection.schema_cache.clear_table_cache!(klass.table_name)
+      end
+    end
+
     klass
   end
 
diff --git a/spec/support/reporting.rb b/spec/support/reporting.rb
new file mode 100644
index 000000000..ed970d2bb
--- /dev/null
+++ b/spec/support/reporting.rb
@@ -0,0 +1,11 @@
+module Reporting
+  def silence_stream(stream)
+    old_stream = stream.dup
+    stream.reopen(RbConfig::CONFIG['host_os'] =~ /mswin|mingw/ ? 'NUL:' : '/dev/null')
+    stream.sync = true
+    yield
+  ensure
+    stream.reopen(old_stream)
+    old_stream.close
+  end
+end