diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 6adf848..547cc10 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -8,17 +8,23 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        gemfile: [rails_4.0.0.gemfile, rails_5.0.0.gemfile, rails_5.2.3.gemfile, rails_6.0.0.gemfile, rails_6.1.0.gemfile, rails_main.gemfile]
-        ruby_version: [2.4, 2.5, 2.6, 2.7]
+        gemfile: [rails_5.2.0.gemfile, rails_6.0.0.gemfile, rails_6.1.0.gemfile, rails_main.gemfile]
+        ruby_version: [2.3, 2.4, 2.5, 2.6, 2.7]
         exclude:
+          - gemfile: rails_main.gemfile
+            ruby_version: 2.3
           - gemfile: rails_main.gemfile
             ruby_version: 2.4
           - gemfile: rails_main.gemfile
             ruby_version: 2.5
           - gemfile: rails_main.gemfile
             ruby_version: 2.6
+          - gemfile: rails_6.0.0.gemfile
+            ruby_version: 2.3
           - gemfile: rails_6.0.0.gemfile
             ruby_version: 2.4
+          - gemfile: rails_6.1.0.gemfile
+            ruby_version: 2.3
           - gemfile: rails_6.1.0.gemfile
             ruby_version: 2.4
     env:
diff --git a/spec/gemfiles/rails_4.0.0.gemfile b/spec/gemfiles/rails_4.0.0.gemfile
deleted file mode 100644
index 8561c73..0000000
--- a/spec/gemfiles/rails_4.0.0.gemfile
+++ /dev/null
@@ -1,6 +0,0 @@
-source 'https://rubygems.org'
-
-gemspec path: '../..'
-
-gem 'rails', '~> 4.0.0'
-gem 'sqlite3', '~> 1.3.6'
diff --git a/spec/gemfiles/rails_5.0.0.gemfile b/spec/gemfiles/rails_5.2.0.gemfile
similarity index 69%
rename from spec/gemfiles/rails_5.0.0.gemfile
rename to spec/gemfiles/rails_5.2.0.gemfile
index 1480a7e..0610b6d 100644
--- a/spec/gemfiles/rails_5.0.0.gemfile
+++ b/spec/gemfiles/rails_5.2.0.gemfile
@@ -2,4 +2,4 @@ source 'https://rubygems.org'
 
 gemspec path: '../..'
 
-gem 'rails', '~> 5.0.0'
+gem 'rails', '~> 5.2.0'
diff --git a/spec/gemfiles/rails_5.2.3.gemfile b/spec/gemfiles/rails_5.2.3.gemfile
deleted file mode 100644
index 32d3707..0000000
--- a/spec/gemfiles/rails_5.2.3.gemfile
+++ /dev/null
@@ -1,5 +0,0 @@
-source 'https://rubygems.org'
-
-gemspec path: '../..'
-
-gem 'rails', '~> 5.2.3'
diff --git a/yaaf.gemspec b/yaaf.gemspec
index 7bba711..4eb5bfb 100644
--- a/yaaf.gemspec
+++ b/yaaf.gemspec
@@ -19,8 +19,8 @@ Gem::Specification.new do |spec|
   spec.files = Dir['LICENSE.txt', 'README.md', 'lib/**/*']
   spec.require_paths = ['lib']
 
-  spec.add_dependency 'activemodel', ['>= 4', '< 7']
-  spec.add_dependency 'activerecord', ['>= 4', '< 7']
+  spec.add_dependency 'activemodel', ['>= 5.2', '< 7']
+  spec.add_dependency 'activerecord', ['>= 5.2', '< 7']
 
   spec.add_development_dependency 'database_cleaner-active_record', '~> 1.8.0'
   spec.add_development_dependency 'rake', '~> 13.0.1'