diff --git a/.github/workflows/test-external.yaml b/.github/workflows/test-external.yaml
index 214149c..cbff675 100644
--- a/.github/workflows/test-external.yaml
+++ b/.github/workflows/test-external.yaml
@@ -20,7 +20,6 @@ jobs:
           - macos
         
         ruby:
-          - "2.7"
           - "3.0"
           - "3.1"
           - "3.2"
diff --git a/.github/workflows/test.yaml b/.github/workflows/test.yaml
index 5c765b6..942ede7 100644
--- a/.github/workflows/test.yaml
+++ b/.github/workflows/test.yaml
@@ -21,7 +21,6 @@ jobs:
           - macos
         
         ruby:
-          - "2.7"
           - "3.0"
           - "3.1"
           - "3.2"
diff --git a/gems.rb b/gems.rb
index b2a032b..a3d1fdd 100644
--- a/gems.rb
+++ b/gems.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 # Released under the MIT License.
-# Copyright, 2020-2023, by Samuel Williams.
+# Copyright, 2019-2023, by Samuel Williams.
 
 source "https://rubygems.org"
 
@@ -16,6 +16,9 @@
 end
 
 group "test" do
+	gem "covered"
+	gem "sus"
+	
 	gem "bake-test"
 	gem "bake-test-external"
 end
diff --git a/protocol-http2.gemspec b/protocol-http2.gemspec
index 1d5d0ef..18cbf7c 100644
--- a/protocol-http2.gemspec
+++ b/protocol-http2.gemspec
@@ -17,12 +17,8 @@ Gem::Specification.new do |spec|
 	
 	spec.files = Dir.glob(['{lib}/**/*', '*.md'], File::FNM_DOTMATCH, base: __dir__)
 	
-	spec.required_ruby_version = ">= 2.7"
+	spec.required_ruby_version = ">= 2.7.6"
 	
 	spec.add_dependency "protocol-hpack", "~> 1.4"
 	spec.add_dependency "protocol-http", "~> 0.18"
-	
-	spec.add_development_dependency "bundler"
-	spec.add_development_dependency "covered"
-	spec.add_development_dependency "sus"
 end
diff --git a/readme.md b/readme.md
index a86cc58..22afb3d 100644
--- a/readme.md
+++ b/readme.md
@@ -96,3 +96,11 @@ We welcome contributions to this project.
 3.  Commit your changes (`git commit -am 'Add some feature'`).
 4.  Push to the branch (`git push origin my-new-feature`).
 5.  Create new Pull Request.
+
+### Developer Certificate of Origin
+
+This project uses the [Developer Certificate of Origin](https://developercertificate.org/). All contributors to this project must agree to this document to have their contributions accepted.
+
+### Contributor Covenant
+
+This project is governed by [Contributor Covenant](https://www.contributor-covenant.org/). All contributors and participants agree to abide by its terms.
diff --git a/test/protocol/http2.rb b/test/protocol/http2.rb
index 53d3cd8..7b937d0 100644
--- a/test/protocol/http2.rb
+++ b/test/protocol/http2.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 # Released under the MIT License.
-# Copyright, 2019-2023, by Samuel Williams.
+# Copyright, 2023, by Samuel Williams.
 
 require 'protocol/http2/version'
 
diff --git a/test/protocol/http2/frame.rb b/test/protocol/http2/frame.rb
index 0f6582b..3c0cd2f 100644
--- a/test/protocol/http2/frame.rb
+++ b/test/protocol/http2/frame.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 # Released under the MIT License.
-# Copyright, 2019-2023, by Samuel Williams.
+# Copyright, 2023, by Samuel Williams.
 
 require 'protocol/http2/frame'
 
diff --git a/test/protocol/http2/framer.rb b/test/protocol/http2/framer.rb
index 52e4403..67c2217 100644
--- a/test/protocol/http2/framer.rb
+++ b/test/protocol/http2/framer.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 # Released under the MIT License.
-# Copyright, 2019-2023, by Samuel Williams.
+# Copyright, 2023, by Samuel Williams.
 
 require 'protocol/http2/framer'
 
diff --git a/test/protocol/http2/settings.rb b/test/protocol/http2/settings.rb
index 1862758..2f1153b 100644
--- a/test/protocol/http2/settings.rb
+++ b/test/protocol/http2/settings.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 # Released under the MIT License.
-# Copyright, 2019-2023, by Samuel Williams.
+# Copyright, 2023, by Samuel Williams.
 
 require 'protocol/http2/settings_frame'
 
diff --git a/test/protocol/http2/window.rb b/test/protocol/http2/window.rb
index 6ef745d..4456a9b 100644
--- a/test/protocol/http2/window.rb
+++ b/test/protocol/http2/window.rb
@@ -55,4 +55,4 @@
 			expect(window.wanted).to be == 200
 		end
 	end
-end
\ No newline at end of file
+end