diff --git a/.github/workflows/run_tests_CI.yml b/.github/workflows/run_tests_CI.yml
deleted file mode 100644
index 836810e..0000000
--- a/.github/workflows/run_tests_CI.yml
+++ /dev/null
@@ -1,32 +0,0 @@
-# This workflow uses actions that are not certified by GitHub.
-# They are provided by a third-party and are governed by
-# separate terms of service, privacy policy, and support
-# documentation.
-# This workflow will download a prebuilt Ruby version, install dependencies and run tests with Rake
-# For more information see: https://github.com/marketplace/actions/setup-ruby-jruby-and-truffleruby
-
-name: Ruby
-
-on:
-  pull_request:
-  push: { branches: talk-api-version }
-
-permissions:
-  contents: read
-
-jobs:
-  test:
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        ruby-version: ['2.6']
-
-    steps:
-    - uses: actions/checkout@v4
-    - name: Set up Ruby
-      uses: ruby/setup-ruby@v1
-      with:
-        ruby-version: ${{ matrix.ruby-version }}
-        bundler-cache: true
-    - name: Run tests
-      run: bundle exec rake test
\ No newline at end of file
diff --git a/.ruby-version b/.ruby-version
index 5154b3f..7fa1d1e 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-2.6
+2.0.0-p353
diff --git a/Dockerfile b/Dockerfile
index f19c35c..a4df1a3 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM ruby:2.6
+FROM ruby:2.5
 
 RUN apt-get update && apt-get install -y nano vim
 
diff --git a/restpack_serializer.gemspec b/restpack_serializer.gemspec
index bc7d8cb..bfcfc43 100644
--- a/restpack_serializer.gemspec
+++ b/restpack_serializer.gemspec
@@ -17,17 +17,17 @@ Gem::Specification.new do |gem|
   gem.test_files    = gem.files.grep(%r{^(test|spec|features)/})
   gem.require_paths = ["lib"]
 
-  gem.add_dependency 'activesupport', ['>= 5.0.0', '< 7.1']
-  gem.add_dependency 'activerecord', ['>= 5.0.0', '< 7.1']
+  gem.add_dependency 'activesupport', ['>= 4.0.3', '< 6.0']
+  gem.add_dependency 'activerecord', ['>= 4.0.3', '< 6.0']
   gem.add_dependency 'kaminari', '< 2.0'
 
   gem.add_development_dependency 'restpack_gem', '~> 0.0.9'
   gem.add_development_dependency 'rake', '~> 10.0.3'
   gem.add_development_dependency 'guard-rspec', '~> 2.5.4'
-  gem.add_development_dependency 'factory_girl'
-  gem.add_development_dependency 'sqlite3', '< 1.6'
+  gem.add_development_dependency 'factory_girl', '~> 4.2.0'
+  gem.add_development_dependency 'sqlite3', '~> 1.3.7'
   gem.add_development_dependency 'database_cleaner', '~> 1.0.1'
   gem.add_development_dependency 'rspec'
   gem.add_development_dependency 'bump'
-  gem.add_development_dependency 'protected_attributes_continued'
+  gem.add_development_dependency 'protected_attributes', '~> 1.0.5'
 end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 5a2e6f3..4b0b710 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -1,5 +1,4 @@
 require 'rspec'
-require 'ostruct'
 require './lib/restpack_serializer'
 require './spec/fixtures/db'
 require './spec/fixtures/serializers'