diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4b69b7e..1117539 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -19,7 +19,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: [2.6, 2.7, '3.0', 3.1, 3.2, ruby-head, jruby]
+        ruby: ['3.0', 3.1, 3.2, ruby-head, jruby]
     steps:
       - name: Clone repository
         uses: actions/checkout@v3
diff --git a/Gemfile b/Gemfile
index 4c9335f..592a083 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,10 +2,11 @@ source "https://rubygems.org"
 
 gemspec
 
-gem 'rack-rdf',           git: "https://github.com/ruby-rdf/rack-rdf",     branch: "develop"
-gem "rdf",                git: "https://github.com/ruby-rdf/rdf",          branch: "develop"
-gem 'rdf-turtle',         git: "https://github.com/ruby-rdf/rdf-turtle",   branch: "develop"
+gem 'rdf',                git: 'https://github.com/ruby-rdf/rdf.git',          branch: 'develop'
+gem 'rack-rdf',           git: 'https://github.com/ruby-rdf/rack-rdf.git',     branch: 'develop'
 
 group :development do
-  gem "byebug",           platforms: :mri
+  gem 'byebug',           platforms: :mri
+  gem 'ebnf',             git: 'https://github.com/dryruby/ebnf.git',          branch: 'develop'
+  gem 'rdf-turtle',       git: 'https://github.com/ruby-rdf/rdf-turtle.git',   branch: 'develop'
 end
diff --git a/README.md b/README.md
index 43c6763..4d334d7 100644
--- a/README.md
+++ b/README.md
@@ -119,8 +119,8 @@ operation and details of the content negotiation.
 
 ## Dependencies
 
-* [Sinatra](https://rubygems.org/gems/sinatra) (~> 3.0)
-* [Rack::RDF](https://rubygems.org/gems/rack-rdf) (~> 3.2)
+* [Sinatra](https://rubygems.org/gems/sinatra) (~> 3.1)
+* [Rack::RDF](https://rubygems.org/gems/rack-rdf) (~> 3.3)
 
 ## Installation
 
diff --git a/VERSION b/VERSION
index e4604e3..15a2799 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-3.2.1
+3.3.0
diff --git a/sinatra-rdf.gemspec b/sinatra-rdf.gemspec
index 90654e7..64bab26 100755
--- a/sinatra-rdf.gemspec
+++ b/sinatra-rdf.gemspec
@@ -27,10 +27,10 @@ Gem::Specification.new do |gem|
   gem.executables        = %w()
   gem.require_paths      = %w(lib)
 
-  gem.required_ruby_version      = '>= 2.6'
+  gem.required_ruby_version      = '>= 3.0'
   gem.requirements               = []
-  gem.add_runtime_dependency     'rack-rdf',        '~> 3.2', '>= 3.2.3'
-  gem.add_runtime_dependency     'sinatra',         '~> 3.0', '>= 3.0.5'
+  gem.add_runtime_dependency     'rack-rdf',        '~> 3.3'
+  gem.add_runtime_dependency     'sinatra',         '~> 3.1'
 
   gem.add_development_dependency 'yard' ,           '~> 0.9'
   gem.add_development_dependency 'rspec',           '~> 3.12'