diff --git a/.github/CONTRIBUTING.md b/.github/CONTRIBUTING.md
index f4b812ec..7c976673 100644
--- a/.github/CONTRIBUTING.md
+++ b/.github/CONTRIBUTING.md
@@ -35,7 +35,12 @@ ask for whatever help you need, but it's your job to fix it.
 
 ## Development
 
-Install gems with `bundle exec appraisal install`.
+```bash
+gem install bundler
+bundle
+bundle exec appraisal install
+bundle exec appraisal update # occasionally
+```
 
 Testing is a little awkward because the test suite:
 
@@ -43,13 +48,10 @@ Testing is a little awkward because the test suite:
 1. Contains a "dummy" rails app with three databases (test, foo, and bar)
 1. Supports three different RDBMS': sqlite, mysql, and postgres
 
-### Test sqlite, AR 4
+### Test sqlite, AR 6
 
 ```
-DB=sqlite bundle exec appraisal ar-4.2 rake
-
-# Run a single test
-DB=sqlite bundle exec appraisal ar-4.2 rspec spec/paper_trail_spec.rb
+DB=sqlite bundle exec appraisal ar-6.0 rake
 ```
 
 ### Test sqlite, AR 5
diff --git a/.rubocop.yml b/.rubocop.yml
index f24a14ad..eb41466a 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -16,15 +16,12 @@ AllCops:
     - spec/dummy_app/db/schema.rb # Generated, out of our control
 
   # Set to lowest supported version
-  TargetRubyVersion: 2.3
+  TargetRubyVersion: 2.4
 
 Bundler/OrderedGems:
   Exclude:
     - gemfiles/* # generated by Appraisal
 
-Layout/AlignParameters:
-  EnforcedStyle: with_fixed_indentation
-
 Layout/DotPosition:
   EnforcedStyle: trailing
 
@@ -32,16 +29,25 @@ Layout/DotPosition:
 Layout/EmptyLineAfterGuardClause:
   Enabled: false
 
-Layout/IndentHeredoc:
+Layout/HeredocIndentation:
   Exclude:
     - paper_trail.gemspec
 
+# The Ruby Style Guide recommends to "Limit lines to 80 characters."
+# (https://github.com/bbatsov/ruby-style-guide#80-character-limits)
+# Please aim for 80, but up to 100 is OK.
+Layout/LineLength:
+  Max: 100
+
 Layout/MultilineMethodCallIndentation:
   EnforcedStyle: indented
 
 Layout/MultilineOperationIndentation:
   EnforcedStyle: indented
 
+Layout/ParameterAlignment:
+  EnforcedStyle: with_fixed_indentation
+
 # Use exactly one space on each side of an operator. Do not align operators
 # because it makes the code harder to edit, and makes lines unnecessarily long.
 Layout/SpaceAroundOperators:
@@ -61,12 +67,6 @@ Metrics/BlockLength:
 Metrics/ClassLength:
   Enabled: false
 
-# The Ruby Style Guide recommends to "Limit lines to 80 characters."
-# (https://github.com/bbatsov/ruby-style-guide#80-character-limits)
-# Please aim for 80, but up to 100 is OK.
-Metrics/LineLength:
-  Max: 100
-
 # The number of lines in a method is not a useful metric compared to `AbcSize`.
 # It's common to have very long methods (> 50 lines) which are quite simple. For
 # example, a method that returns a long string with only a few interpolations.
@@ -92,12 +92,12 @@ Naming/HeredocDelimiterNaming:
   Enabled: false
 
 Naming/PredicateName:
-  NameWhitelist: has_paper_trail
+  AllowedMethods: has_paper_trail
 
 # Too subtle to lint.
 # Two-letter param names are OK. Consider `send_email(to:, cc:)`.
 # Even one-letter names are OK. Consider `draw_point(x, y)`.
-Naming/UncommunicativeMethodParamName:
+Naming/MethodParameterName:
   Enabled: false
 
 # This cop does not seem to work in rubocop-rspec 1.28.0
@@ -147,6 +147,10 @@ Style/FrozenStringLiteralComment:
 Style/GuardClause:
   Enabled: false
 
+# `hash.keys.each` is totally fine.
+Style/HashEachMethods:
+  Enabled: false
+
 # Only use postfix (modifier) conditionals for utterly simple statements.
 # As a rule of thumb, the entire statement should not exceed 60 chars.
 # Rubocop used to support this level of configuration, but no longer does.
diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index b96afd3b..a86e8bc0 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -3,7 +3,7 @@ require: rubocop-rspec
 # Remove these configuration records
 # one by one as the offenses are removed from the code base.
 
-Layout/AlignArguments:
+Layout/ArgumentAlignment:
   Enabled: false
 
 Metrics/AbcSize:
@@ -38,3 +38,11 @@ RSpec/NestedGroups:
 # interface is a public API, so that would be a breaking change.
 Security/YAMLLoad:
   Enabled: false
+
+# We want this, but not until we drop support for ruby 2.4
+Style/HashTransformKeys:
+  Enabled: false
+
+# We want this, but not until we drop support for ruby 2.4
+Style/HashTransformValues:
+  Enabled: false
diff --git a/.travis.yml b/.travis.yml
index 318c302d..6aa2052f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,11 +1,9 @@
 language: ruby
 cache: bundler
 
-# For ruby compatibility, we test the highest and lowest minor versions only.
-# For example, if our gemspec says `required_ruby_version = ">= 2.3.0"`, and
-# ruby 2.5.0 has just been released, then we test 2.3 and 2.5, but not 2.4.
+# For ruby, we test the highest and lowest minor versions only.
 rvm:
-  - 2.3
+  - 2.4
   - 2.7
 
 env:
@@ -29,13 +27,12 @@ before_install:
   - gem update bundler
 
 gemfile:
-  - gemfiles/ar_5.1.gemfile
   - gemfiles/ar_5.2.gemfile
   - gemfiles/ar_6.0.gemfile
 matrix:
   exclude:
     # rails 6 requires ruby >= 2.5.0
-    - rvm: 2.3
+    - rvm: 2.4
       gemfile: gemfiles/ar_6.0.gemfile
   fast_finish: true
 services:
diff --git a/Appraisals b/Appraisals
index 3c094342..3a584b18 100644
--- a/Appraisals
+++ b/Appraisals
@@ -9,11 +9,6 @@
 # > the version from the appraisal takes precedence.
 # > https://github.com/thoughtbot/appraisal
 
-appraise "ar-5.1" do
-  gem "activerecord", [">= 5.1.6.2", "< 5.2"]
-  gem "rails-controller-testing", "~> 1.0.2"
-end
-
 appraise "ar-5.2" do
   gem "activerecord", [">= 5.2.2.1", "< 5.3"]
   gem "rails-controller-testing", "~> 1.0.2"
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 472c93c5..489c2017 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -25,7 +25,9 @@ recommendations of [keepachangelog.com](http://keepachangelog.com/).
 
 ### Dependencies
 
-- Drop support for rails 4 (reached EOL on 2019-08-15)
+- Drop support for rails <= 5.1 (reached EOL when 6.0 was released,
+  per https://guides.rubyonrails.org/maintenance_policy.html)
+- Drop support for ruby 2.3 (reached EOL on 2019-04-01)
 
 ## 10.3.1 (2019-07-31)
 
diff --git a/lib/generators/paper_trail/migration_generator.rb b/lib/generators/paper_trail/migration_generator.rb
index ed6938da..e5588ad4 100644
--- a/lib/generators/paper_trail/migration_generator.rb
+++ b/lib/generators/paper_trail/migration_generator.rb
@@ -28,10 +28,11 @@ module PaperTrail
     end
 
     def migration_version
-      major = ActiveRecord::VERSION::MAJOR
-      if major >= 5
-        "[#{major}.#{ActiveRecord::VERSION::MINOR}]"
-      end
+      format(
+        "[%d.%d]",
+        ActiveRecord::VERSION::MAJOR,
+        ActiveRecord::VERSION::MINOR
+      )
     end
   end
 end
diff --git a/lib/paper_trail/attribute_serializers/cast_attribute_serializer.rb b/lib/paper_trail/attribute_serializers/cast_attribute_serializer.rb
index 73156b20..283e6192 100644
--- a/lib/paper_trail/attribute_serializers/cast_attribute_serializer.rb
+++ b/lib/paper_trail/attribute_serializers/cast_attribute_serializer.rb
@@ -32,50 +32,18 @@ module PaperTrail
       end
     end
 
-    if ::ActiveRecord::VERSION::MAJOR >= 5
-      # This implementation uses AR 5's `serialize` and `deserialize`.
-      class CastAttributeSerializer
-        def serialize(attr, val)
-          AttributeSerializerFactory.for(@klass, attr).serialize(val)
-        end
-
-        def deserialize(attr, val)
-          if defined_enums[attr] && val.is_a?(::String)
-            # Because PT 4 used to save the string version of enums to `object_changes`
-            val
-          else
-            AttributeSerializerFactory.for(@klass, attr).deserialize(val)
-          end
-        end
+    # Uses AR 5's `serialize` and `deserialize`.
+    class CastAttributeSerializer
+      def serialize(attr, val)
+        AttributeSerializerFactory.for(@klass, attr).serialize(val)
       end
-    else
-      # This implementation uses AR 4.2's `type_cast_for_database`. For
-      # versions of AR < 4.2 we provide an implementation of
-      # `type_cast_for_database` in our shim attribute type classes,
-      # `NoOpAttribute` and `SerializedAttribute`.
-      class CastAttributeSerializer
-        def serialize(attr, val)
-          castable_val = val
-          if defined_enums[attr]
-            # `attr` is an enum. Find the number that corresponds to `val`. If `val` is
-            # a number already, there won't be a corresponding entry, just use `val`.
-            castable_val = defined_enums[attr][val] || val
-          end
-          @klass.type_for_attribute(attr).type_cast_for_database(castable_val)
-        end
 
-        def deserialize(attr, val)
-          if defined_enums[attr] && val.is_a?(::String)
-            # Because PT 4 used to save the string version of enums to `object_changes`
-            val
-          else
-            val = @klass.type_for_attribute(attr).type_cast_from_database(val)
-            if defined_enums[attr]
-              defined_enums[attr].key(val)
-            else
-              val
-            end
-          end
+      def deserialize(attr, val)
+        if defined_enums[attr] && val.is_a?(::String)
+          # Because PT 4 used to save the string version of enums to `object_changes`
+          val
+        else
+          AttributeSerializerFactory.for(@klass, attr).deserialize(val)
         end
       end
     end
diff --git a/lib/paper_trail/compatibility.rb b/lib/paper_trail/compatibility.rb
index 16f1d755..e7bd25e7 100644
--- a/lib/paper_trail/compatibility.rb
+++ b/lib/paper_trail/compatibility.rb
@@ -17,8 +17,8 @@ module PaperTrail
   # newer rails versions. Most PT users should avoid incompatible rails
   # versions.
   module Compatibility
-    ACTIVERECORD_GTE = ">= 4.2"
-    ACTIVERECORD_LT = "< 6.1"
+    ACTIVERECORD_GTE = ">= 5.2" # enforced in gemspec
+    ACTIVERECORD_LT = "< 6.1" # not enforced in gemspec
 
     E_INCOMPATIBLE_AR = <<-EOS
       PaperTrail %s is not compatible with ActiveRecord %s. We allow PT
diff --git a/lib/paper_trail/frameworks/rails/controller.rb b/lib/paper_trail/frameworks/rails/controller.rb
index f388e75f..99881042 100644
--- a/lib/paper_trail/frameworks/rails/controller.rb
+++ b/lib/paper_trail/frameworks/rails/controller.rb
@@ -25,9 +25,7 @@ module PaperTrail
       # @api public
       def user_for_paper_trail
         return unless defined?(current_user)
-        ActiveSupport::VERSION::MAJOR >= 4 ? current_user.try!(:id) : current_user.try(:id)
-      rescue NoMethodError
-        current_user
+        current_user.try(:id) || current_user
       end
 
       # Returns any information about the controller or request that you
diff --git a/lib/paper_trail/model_config.rb b/lib/paper_trail/model_config.rb
index 96e42afe..d18894da 100644
--- a/lib/paper_trail/model_config.rb
+++ b/lib/paper_trail/model_config.rb
@@ -128,10 +128,6 @@ module PaperTrail
 
     private
 
-    def active_record_gem_version
-      Gem::Version.new(ActiveRecord::VERSION::STRING)
-    end
-
     # Raises an error if the provided class is an `abstract_class`.
     # @api private
     def assert_concrete_activerecord_class(class_name)
@@ -141,8 +137,7 @@ module PaperTrail
     end
 
     def cannot_record_after_destroy?
-      Gem::Version.new(ActiveRecord::VERSION::STRING).release >= Gem::Version.new("5") &&
-        ::ActiveRecord::Base.belongs_to_required_by_default
+      ::ActiveRecord::Base.belongs_to_required_by_default
     end
 
     # Some options require the presence of the `item_subtype` column. Currently
diff --git a/lib/paper_trail/reifier.rb b/lib/paper_trail/reifier.rb
index 44ce5095..dbdd730d 100644
--- a/lib/paper_trail/reifier.rb
+++ b/lib/paper_trail/reifier.rb
@@ -88,9 +88,7 @@ module PaperTrail
       #
       # @api private
       def reify_attribute(k, v, model, version)
-        enums = model.class.respond_to?(:defined_enums) ? model.class.defined_enums : {}
-        is_enum_without_type_caster = ::ActiveRecord::VERSION::MAJOR < 5 && enums.key?(k)
-        if model.has_attribute?(k) && !is_enum_without_type_caster
+        if model.has_attribute?(k)
           model[k.to_sym] = v
         elsif model.respond_to?("#{k}=")
           model.send("#{k}=", v)
diff --git a/paper_trail.gemspec b/paper_trail.gemspec
index d6ec68be..acb0f01a 100644
--- a/paper_trail.gemspec
+++ b/paper_trail.gemspec
@@ -26,7 +26,10 @@ has been destroyed.
   s.require_paths = ["lib"]
 
   s.required_rubygems_version = ">= 1.3.6"
-  s.required_ruby_version = ">= 2.3.0"
+
+  # Ruby 2.4 reaches EoL at the end of March of 2020
+  # https://www.ruby-lang.org/en/news/2019/10/02/ruby-2-4-9-released/
+  s.required_ruby_version = ">= 2.4.0"
 
   # We no longer specify a maximum rails version.
   # See discussion in paper_trail/compatibility.rb
@@ -41,7 +44,7 @@ has been destroyed.
   s.add_development_dependency "paper_trail-association_tracking", "~> 2.0.0"
   s.add_development_dependency "rake", "~> 12.3"
   s.add_development_dependency "rspec-rails", "~> 3.8"
-  s.add_development_dependency "rubocop", "~> 0.74.0"
+  s.add_development_dependency "rubocop", "~> 0.80.0"
   s.add_development_dependency "rubocop-performance", "~> 1.4"
   s.add_development_dependency "rubocop-rspec", "~> 1.35"
 
diff --git a/spec/controllers/articles_controller_spec.rb b/spec/controllers/articles_controller_spec.rb
index c524eee2..a5dac24c 100644
--- a/spec/controllers/articles_controller_spec.rb
+++ b/spec/controllers/articles_controller_spec.rb
@@ -9,7 +9,7 @@ RSpec.describe ArticlesController, type: :controller do
 
       it "returns true" do
         expect(PaperTrail.enabled?).to eq(true)
-        post :create, params_wrapper(article: { title: "Doh", content: FFaker::Lorem.sentence })
+        post :create, params: { article: { title: "Doh", content: FFaker::Lorem.sentence } }
         expect(assigns(:article)).not_to be_nil
         expect(PaperTrail.request.enabled?).to eq(true)
         expect(assigns(:article).versions.length).to eq(1)
@@ -21,7 +21,7 @@ RSpec.describe ArticlesController, type: :controller do
     context "PaperTrail.enabled? == false" do
       it "returns false" do
         expect(PaperTrail.enabled?).to eq(false)
-        post :create, params_wrapper(article: { title: "Doh", content: FFaker::Lorem.sentence })
+        post :create, params: { article: { title: "Doh", content: FFaker::Lorem.sentence } }
         expect(PaperTrail.request.enabled?).to eq(false)
         expect(assigns(:article).versions.length).to eq(0)
       end
diff --git a/spec/controllers/widgets_controller_spec.rb b/spec/controllers/widgets_controller_spec.rb
index 9768699b..598dca8a 100644
--- a/spec/controllers/widgets_controller_spec.rb
+++ b/spec/controllers/widgets_controller_spec.rb
@@ -10,7 +10,7 @@ RSpec.describe WidgetsController, type: :controller, versioning: true do
   describe "#create" do
     context "PT enabled" do
       it "stores information like IP address in version" do
-        post(:create, params_wrapper(widget: { name: "Flugel" }))
+        post(:create, params: { widget: { name: "Flugel" } })
         widget = assigns(:widget)
         expect(widget.versions.length).to(eq(1))
         expect(widget.versions.last.whodunnit.to_i).to(eq(153))
@@ -20,7 +20,7 @@ RSpec.describe WidgetsController, type: :controller, versioning: true do
 
       it "controller metadata methods should get evaluated" do
         request.env["HTTP_USER_AGENT"] = "User-Agent"
-        post :create, params_wrapper(widget: { name: "Flugel" })
+        post :create, params: { widget: { name: "Flugel" } }
         expect(PaperTrail.request.enabled?).to eq(true)
         expect(PaperTrail.request.whodunnit).to(eq(153))
         expect(PaperTrail.request.controller_info.present?).to(eq(true))
@@ -32,7 +32,7 @@ RSpec.describe WidgetsController, type: :controller, versioning: true do
     context "PT disabled" do
       it "does not save a version, and metadata is not set" do
         request.env["HTTP_USER_AGENT"] = "Disable User-Agent"
-        post :create, params_wrapper(widget: { name: "Flugel" })
+        post :create, params: { widget: { name: "Flugel" } }
         expect(assigns(:widget).versions.length).to(eq(0))
         expect(PaperTrail.request.enabled?).to eq(false)
         expect(PaperTrail.request.whodunnit).to be_nil
@@ -44,17 +44,17 @@ RSpec.describe WidgetsController, type: :controller, versioning: true do
   describe "#destroy" do
     it "can be disabled" do
       request.env["HTTP_USER_AGENT"] = "Disable User-Agent"
-      post(:create, params_wrapper(widget: { name: "Flugel" }))
+      post(:create, params: { widget: { name: "Flugel" } })
       w = assigns(:widget)
       expect(w.versions.length).to(eq(0))
-      delete(:destroy, params_wrapper(id: w.id))
+      delete(:destroy, params: { id: w.id })
       expect(PaperTrail::Version.with_item_keys("Widget", w.id).size).to(eq(0))
     end
 
     it "stores information like IP address in version" do
       w = Widget.create(name: "Roundel")
       expect(w.versions.length).to(eq(1))
-      delete(:destroy, params_wrapper(id: w.id))
+      delete(:destroy, params: { id: w.id })
       widget = assigns(:widget)
       expect(widget.versions.length).to(eq(2))
       expect(widget.versions.last.ip).to(eq("127.0.0.1"))
@@ -67,7 +67,7 @@ RSpec.describe WidgetsController, type: :controller, versioning: true do
     it "stores information like IP address in version" do
       w = Widget.create(name: "Duvel")
       expect(w.versions.length).to(eq(1))
-      put(:update, params_wrapper(id: w.id, widget: { name: "Bugle" }))
+      put(:update, params: { id: w.id, widget: { name: "Bugle" } })
       widget = assigns(:widget)
       expect(widget.versions.length).to(eq(2))
       expect(widget.versions.last.whodunnit.to_i).to(eq(153))
@@ -77,10 +77,10 @@ RSpec.describe WidgetsController, type: :controller, versioning: true do
 
     it "can be disabled" do
       request.env["HTTP_USER_AGENT"] = "Disable User-Agent"
-      post(:create, params_wrapper(widget: { name: "Flugel" }))
+      post(:create, params: { widget: { name: "Flugel" } })
       w = assigns(:widget)
       expect(w.versions.length).to(eq(0))
-      put(:update, params_wrapper(id: w.id, widget: { name: "Bugle" }))
+      put(:update, params: { id: w.id, widget: { name: "Bugle" } })
       widget = assigns(:widget)
       expect(widget.versions.length).to(eq(0))
     end
diff --git a/spec/dummy_app/db/migrate/20110208155312_set_up_test_tables.rb b/spec/dummy_app/db/migrate/20110208155312_set_up_test_tables.rb
index 422cc9d6..ab260a97 100644
--- a/spec/dummy_app/db/migrate/20110208155312_set_up_test_tables.rb
+++ b/spec/dummy_app/db/migrate/20110208155312_set_up_test_tables.rb
@@ -6,13 +6,7 @@
 # Starting with AR 5.1, we must specify which version of AR we are using.
 # I tried using `const_get` but I got a `NameError`, then I learned about
 # `::ActiveRecord::Migration::Current`.
-class SetUpTestTables < (
-  if ::ActiveRecord::VERSION::MAJOR >= 5
-    ::ActiveRecord::Migration::Current
-  else
-    ::ActiveRecord::Migration
-  end
-)
+class SetUpTestTables < ::ActiveRecord::Migration::Current
   MYSQL_ADAPTERS = [
     "ActiveRecord::ConnectionAdapters::MysqlAdapter",
     "ActiveRecord::ConnectionAdapters::Mysql2Adapter"
diff --git a/spec/models/version_spec.rb b/spec/models/version_spec.rb
index 4b90ba76..de35250a 100644
--- a/spec/models/version_spec.rb
+++ b/spec/models/version_spec.rb
@@ -126,11 +126,7 @@ module PaperTrail
 
           before do
             if column_datatype_override
-              # In rails < 5, we use truncation, ie. there is no transaction
-              # around the tests, so we can't use a savepoint.
-              if active_record_gem_version >= ::Gem::Version.new("5")
-                ActiveRecord::Base.connection.execute("SAVEPOINT pgtest;")
-              end
+              ActiveRecord::Base.connection.execute("SAVEPOINT pgtest;")
               %w[object object_changes].each do |column|
                 ActiveRecord::Base.connection.execute(
                   "ALTER TABLE versions DROP COLUMN #{column};"
@@ -147,20 +143,7 @@ module PaperTrail
             PaperTrail.serializer = PaperTrail::Serializers::YAML
 
             if column_datatype_override
-              # In rails < 5, we use truncation, ie. there is no transaction
-              # around the tests, so we can't use a savepoint.
-              if active_record_gem_version >= ::Gem::Version.new("5")
-                ActiveRecord::Base.connection.execute("ROLLBACK TO SAVEPOINT pgtest;")
-              else
-                %w[object object_changes].each do |column|
-                  ActiveRecord::Base.connection.execute(
-                    "ALTER TABLE versions DROP COLUMN #{column};"
-                  )
-                  ActiveRecord::Base.connection.execute(
-                    "ALTER TABLE versions ADD COLUMN #{column} text;"
-                  )
-                end
-              end
+              ActiveRecord::Base.connection.execute("ROLLBACK TO SAVEPOINT pgtest;")
               PaperTrail::Version.reset_column_information
             end
           end
diff --git a/spec/requests/articles_spec.rb b/spec/requests/articles_spec.rb
index f5ef2e0f..2d77ca0f 100644
--- a/spec/requests/articles_spec.rb
+++ b/spec/requests/articles_spec.rb
@@ -11,7 +11,7 @@ RSpec.describe "Articles management", type: :request, order: :defined do
     it "does not create a version" do
       expect(PaperTrail.request).to be_enabled
       expect {
-        post articles_path, params_wrapper(valid_params)
+        post articles_path, params: valid_params
       }.not_to change(PaperTrail::Version, :count)
     end
   end
@@ -22,7 +22,7 @@ RSpec.describe "Articles management", type: :request, order: :defined do
     context "`current_user` method returns a `String`" do
       it "sets that value as the `whodunnit`" do
         expect {
-          post articles_path, params_wrapper(valid_params)
+          post articles_path, params: valid_params
         }.to change(PaperTrail::Version, :count).by(1)
         expect(article.title).to eq("Doh")
         expect(article.versions.last.whodunnit).to eq("foobar")
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index dc49df4e..3240e579 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -28,21 +28,6 @@ RSpec.configure do |config|
   Kernel.srand config.seed
 end
 
-def active_record_gem_version
-  Gem::Version.new(ActiveRecord::VERSION::STRING)
-end
-
-# Wrap args in a hash to support the ActionController::TestCase and
-# ActionDispatch::Integration HTTP request method switch to keyword args
-# (see https://github.com/rails/rails/blob/master/actionpack/CHANGELOG.md)
-def params_wrapper(args)
-  if defined?(::Rails) && active_record_gem_version >= Gem::Version.new("5.0.0.beta1")
-    { params: args }
-  else
-    args
-  end
-end
-
 require File.expand_path("dummy_app/config/environment", __dir__)
 require "rspec/rails"
 require "paper_trail/frameworks/rspec"
@@ -54,21 +39,5 @@ require_relative "support/paper_trail_spec_migrator"
 
 RSpec.configure do |config|
   config.fixture_path = "#{::Rails.root}/spec/fixtures"
-end
-
-# In rails < 5, some tests seem to require DatabaseCleaner-truncation.
-# Truncation is about three times slower than transaction rollback, so it'll
-# be nice when we can drop support for rails < 5.
-if active_record_gem_version < ::Gem::Version.new("5")
-  require "database_cleaner"
-  DatabaseCleaner.strategy = :truncation
-  RSpec.configure do |config|
-    config.use_transactional_fixtures = false
-    config.before { DatabaseCleaner.start }
-    config.after { DatabaseCleaner.clean }
-  end
-else
-  RSpec.configure do |config|
-    config.use_transactional_fixtures = true
-  end
+  config.use_transactional_fixtures = true
 end