diff --git a/.gitignore b/.gitignore
index be82d15a2f..0ced8f286b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -25,3 +25,5 @@ pkg
 /.idea
 .byebug_history
 gemfiles/.bundle/
+.yardoc
+/doc
diff --git a/.yardopts b/.yardopts
new file mode 100644
index 0000000000..77c591c8c3
--- /dev/null
+++ b/.yardopts
@@ -0,0 +1,13 @@
+-
+CHANGELOG.md
+docs/getting_started.md
+docs/rails_api.md
+docs/customizing_dashboards.md
+docs/customizing_page_views.md
+docs/customizing_attribute_partials.md
+docs/adding_controllers_without_related_model.md
+docs/adding_custom_field_types.md
+docs/authentication.md
+docs/authorization.md
+CODE_OF_CONDUCT.md
+LICENSE.md
diff --git a/Appraisals b/Appraisals
index 63730dc164..0121c3eda2 100644
--- a/Appraisals
+++ b/Appraisals
@@ -1,14 +1,3 @@
-appraise "rails42" do
-  gem "actionpack", "~> 4.2.0"
-  gem "actionview", "~> 4.2.0"
-  gem "activerecord", "~> 4.2.0"
-  gem "pg", "0.21.0"
-
-  group :development, :test do
-    gem "rspec-rails"
-  end
-end
-
 appraise "rails50" do
   gem "actionpack", "~> 5.0.0"
   gem "actionview", "~> 5.0.0"
diff --git a/Gemfile b/Gemfile
index b0a7af82b0..9c2d805766 100644
--- a/Gemfile
+++ b/Gemfile
@@ -21,6 +21,7 @@ group :development, :test do
   gem "factory_bot_rails"
   gem "i18n-tasks", "0.9.31"
   gem "pry-rails"
+  gem "yard"
 end
 
 group :test do
diff --git a/Gemfile.lock b/Gemfile.lock
index 6e9fecde64..6425a0e1c5 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -2,9 +2,9 @@ PATH
   remote: .
   specs:
     administrate (0.14.0)
-      actionpack (>= 4.2)
-      actionview (>= 4.2)
-      activerecord (>= 4.2)
+      actionpack (>= 5.0)
+      actionview (>= 5.0)
+      activerecord (>= 5.0)
       autoprefixer-rails (>= 6.0)
       datetime_picker_rails (~> 0.0.7)
       jquery-rails (>= 4.0)
@@ -53,7 +53,7 @@ GEM
       rake
       thor (>= 0.14.0)
     ast (2.4.0)
-    autoprefixer-rails (9.8.6.1)
+    autoprefixer-rails (9.8.6.3)
       execjs
     awesome_print (1.8.0)
     builder (3.2.4)
@@ -92,7 +92,7 @@ GEM
       railties (>= 5.0.0)
     faker (2.13.0)
       i18n (>= 1.6, < 2)
-    faraday (1.0.0)
+    faraday (1.0.1)
       multipart-post (>= 1.2, < 3)
     ffi (1.13.1)
     formulaic (0.4.1)
@@ -212,7 +212,7 @@ GEM
     selenium-webdriver (3.142.7)
       childprocess (>= 0.5, < 4.0)
       rubyzip (>= 1.2.2)
-    sentry-raven (3.0.0)
+    sentry-raven (3.0.2)
       faraday (>= 1.0)
     shoulda-matchers (4.3.0)
       activesupport (>= 4.2.0)
@@ -243,6 +243,7 @@ GEM
       hashdiff (>= 0.4.0, < 2.0.0)
     xpath (3.2.0)
       nokogiri (~> 1.8)
+    yard (0.9.25)
     zeitwerk (2.3.1)
 
 PLATFORMS
@@ -281,6 +282,7 @@ DEPENDENCIES
   unicorn
   webmock
   xpath (= 3.2.0)
+  yard
 
 BUNDLED WITH
    1.17.3
diff --git a/README.md b/README.md
index bbc32024cc..4ae484b411 100644
--- a/README.md
+++ b/README.md
@@ -46,8 +46,7 @@ To accomplish these goals, Administrate follows a few guiding principles:
 
 ## Getting Started
 
-Administrate supports Rails from 4.2, up to 5.0 and beyond. We support Ruby
-2.4 and up.
+Administrate supports Rails 5.0 onwards. We support Ruby 2.4 and up.
 
 Add Administrate to your Gemfile and re-bundle:
 
@@ -104,7 +103,7 @@ git repository, too.
 
 Please see [CONTRIBUTING.md](/CONTRIBUTING.md).
 
-administrate was originally written by Grayson Wright and is now maintained by
+administrate was originally written by Grace Youngblood and is now maintained by
 Nick Charlton. Many improvements and bugfixes were contributed by the [open
 source
 community](https://github.com/thoughtbot/administrate/graphs/contributors).
diff --git a/administrate.gemspec b/administrate.gemspec
index f9fb33630c..ffdec7ac77 100644
--- a/administrate.gemspec
+++ b/administrate.gemspec
@@ -14,9 +14,9 @@ Gem::Specification.new do |s|
   s.files = Dir["{app,config,db,lib,docs}/**/*", "LICENSE", "Rakefile"]
   s.test_files = Dir["test/**/*"]
 
-  s.add_dependency "actionpack", ">= 4.2"
-  s.add_dependency "actionview", ">= 4.2"
-  s.add_dependency "activerecord", ">= 4.2"
+  s.add_dependency "actionpack", ">= 5.0"
+  s.add_dependency "actionview", ">= 5.0"
+  s.add_dependency "activerecord", ">= 5.0"
 
   s.add_dependency "autoprefixer-rails", ">= 6.0"
   s.add_dependency "datetime_picker_rails", "~> 0.0.7"
diff --git a/app/views/fields/polymorphic/_show.html.erb b/app/views/fields/polymorphic/_show.html.erb
index 42f1ff38a3..27a5645aee 100644
--- a/app/views/fields/polymorphic/_show.html.erb
+++ b/app/views/fields/polymorphic/_show.html.erb
@@ -17,7 +17,7 @@ By default, the relationship is rendered as a link to the associated object.
 %>
 
 <% if field.data %>
-  <% if valid_action?(:show, field.attribute) %>
+  <% if valid_action?(:show, field.data.class) %>
     <%= link_to(
       field.display_associated_resource,
       [namespace, field.data],
diff --git a/docs/adding_controllers_without_related_model.md b/docs/adding_controllers_without_related_model.md
index d5017a0a47..2f812890fa 100644
--- a/docs/adding_controllers_without_related_model.md
+++ b/docs/adding_controllers_without_related_model.md
@@ -1,3 +1,7 @@
+---
+title: Adding Controllers without a related Model
+---
+
 # Adding Controllers without a related Model
 
 Sometimes you may want to add a custom controller that has no resource
diff --git a/gemfiles/rails42.gemfile b/gemfiles/rails42.gemfile
deleted file mode 100644
index ba33da99db..0000000000
--- a/gemfiles/rails42.gemfile
+++ /dev/null
@@ -1,49 +0,0 @@
-# This file was generated by Appraisal
-
-source "https://rubygems.org"
-
-gem "administrate-field-image"
-gem "autoprefixer-rails"
-gem "faker"
-gem "front_matter_parser"
-gem "globalid"
-gem "pg", "0.21.0"
-gem "redcarpet"
-gem "sentry-raven"
-gem "unicorn"
-gem "actionpack", "~> 4.2.0"
-gem "actionview", "~> 4.2.0"
-gem "activerecord", "~> 4.2.0"
-
-group :development, :test do
-  gem "appraisal"
-  gem "awesome_print"
-  gem "bundler-audit", require: false
-  gem "byebug"
-  gem "dotenv-rails"
-  gem "factory_bot_rails"
-  gem "i18n-tasks", "0.9.31"
-  gem "pry-rails"
-  gem "rspec-rails"
-end
-
-group :test do
-  gem "ammeter"
-  gem "capybara", "3.33.0"
-  gem "database_cleaner"
-  gem "formulaic"
-  gem "launchy"
-  gem "pundit"
-  gem "selenium-webdriver"
-  gem "shoulda-matchers"
-  gem "timecop"
-  gem "webmock"
-  gem "xpath", "3.2.0"
-end
-
-group :staging, :production do
-  gem "rack-timeout"
-  gem "uglifier"
-end
-
-gemspec path: "../"
diff --git a/gemfiles/rails50.gemfile b/gemfiles/rails50.gemfile
index 7b0a44eb6a..1fe3600768 100644
--- a/gemfiles/rails50.gemfile
+++ b/gemfiles/rails50.gemfile
@@ -24,6 +24,7 @@ group :development, :test do
   gem "factory_bot_rails"
   gem "i18n-tasks", "0.9.31"
   gem "pry-rails"
+  gem "yard"
   gem "rspec-rails"
 end
 
diff --git a/gemfiles/rails51.gemfile b/gemfiles/rails51.gemfile
index 664ad8d91f..f853732b6e 100644
--- a/gemfiles/rails51.gemfile
+++ b/gemfiles/rails51.gemfile
@@ -24,6 +24,7 @@ group :development, :test do
   gem "factory_bot_rails"
   gem "i18n-tasks", "0.9.31"
   gem "pry-rails"
+  gem "yard"
   gem "rspec-rails"
 end
 
diff --git a/gemfiles/rails52.gemfile b/gemfiles/rails52.gemfile
index 8d5811cc59..5449a086b6 100644
--- a/gemfiles/rails52.gemfile
+++ b/gemfiles/rails52.gemfile
@@ -24,6 +24,7 @@ group :development, :test do
   gem "factory_bot_rails"
   gem "i18n-tasks", "0.9.31"
   gem "pry-rails"
+  gem "yard"
   gem "rspec-rails"
 end
 
diff --git a/gemfiles/rails60.gemfile b/gemfiles/rails60.gemfile
index 602878ef7b..1bf0ef1f3d 100644
--- a/gemfiles/rails60.gemfile
+++ b/gemfiles/rails60.gemfile
@@ -22,6 +22,7 @@ group :development, :test do
   gem "factory_bot_rails"
   gem "i18n-tasks", "0.9.31"
   gem "pry-rails"
+  gem "yard"
   gem "rspec-rails", "~> 4.0.0.beta2"
 end
 
diff --git a/lib/generators/administrate/dashboard/templates/dashboard.rb.erb b/lib/generators/administrate/dashboard/templates/dashboard.rb.erb
index 32c24547d8..7c0a65c0a9 100644
--- a/lib/generators/administrate/dashboard/templates/dashboard.rb.erb
+++ b/lib/generators/administrate/dashboard/templates/dashboard.rb.erb
@@ -21,7 +21,7 @@ class <%= class_name %>Dashboard < Administrate::BaseDashboard
   COLLECTION_ATTRIBUTES = %i[
 <%=
   attributes.first(COLLECTION_ATTRIBUTE_LIMIT).map do |attr|
-    "  #{attr}"
+    "    #{attr}"
   end.join("\n")
 %>
   ].freeze
@@ -31,7 +31,7 @@ class <%= class_name %>Dashboard < Administrate::BaseDashboard
   SHOW_PAGE_ATTRIBUTES = %i[
 <%=
   attributes.map do |attr|
-    "  #{attr}"
+    "    #{attr}"
   end.join("\n")
 %>
   ].freeze
@@ -42,7 +42,7 @@ class <%= class_name %>Dashboard < Administrate::BaseDashboard
   FORM_ATTRIBUTES = %i[
 <%=
   form_attributes.map do |attr|
-    "  #{attr}"
+    "    #{attr}"
   end.join("\n")
 %>
   ].freeze
diff --git a/spec/support/generator_spec_helpers.rb b/spec/support/generator_spec_helpers.rb
index ec9f4e4c12..09bf175566 100644
--- a/spec/support/generator_spec_helpers.rb
+++ b/spec/support/generator_spec_helpers.rb
@@ -55,7 +55,7 @@ def copy_to_generator_root(destination, template)
   config.include GeneratorSpecHelpers
 
   config.before(:example, :generator) do
-    destination File.expand_path("../../../tmp", __FILE__)
+    destination File.expand_path("../../tmp/generator_tests_output", __dir__)
     prepare_destination
   end
 end