diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 7fd23d6..1748e31 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -15,27 +15,39 @@ jobs:
     strategy:
       matrix:
         include:
-          - os: ubuntu-latest
-            ruby: "2.5"
-          - os: ubuntu-latest
-            ruby: "2.6"
           - os: ubuntu-latest
             ruby: "2.7"
+            flags: "--test --cucumber"
           - os: ubuntu-latest
             ruby: "3.0"
+            flags: "--test --cucumber"
           - os: ubuntu-latest
             ruby: "3.1"
+            flags: "--test --cucumber"
           - os: ubuntu-latest
             ruby: "3.2"
-            tool: ci
+            flags: "--test --cucumber"
+          - os: ubuntu-latest
+            ruby: "3.3"
+            flags: "--test --cucumber"
+          - os: ubuntu-latest
+            ruby: "3.4"
+            flags: "--test --cucumber"
+          - os: ubuntu-latest
+            ruby: "3.4"
+            flags: "--rubocop --yard --build"
           - os: ubuntu-latest
             ruby: jruby
+            flags: "--test --cucumber"
           - os: ubuntu-latest
             ruby: truffleruby
+            flags: "--test --cucumber"
           - os: macos-latest
-            ruby: "3.2"
+            ruby: "3.4"
+            flags: "--test --cucumber"
           - os: windows-latest
-            ruby: "3.2"
+            ruby: "3.4"
+            flags: "--test --cucumber"
       fail-fast: false
     runs-on: ${{ matrix.os }}
     steps:
@@ -44,13 +56,11 @@ jobs:
         with:
           ruby-version: ${{ matrix.ruby }}
       - name: Checkout repo
-        uses: actions/checkout@v2
+        uses: actions/checkout@v5
       - name: Install dependencies
         shell: bash
         run: "bundle install && gem install --no-document toys"
-      - name: Run ${{ matrix.tool || 'test' }}
+      - name: Run ${{ matrix.flags }}
         shell: bash
-        env:
-          MT_COMPAT: "true"
         run: |
-          toys "${{ matrix.tool || 'test' }}" < /dev/null
+          toys ci --only ${{ matrix.flags }} < /dev/null
diff --git a/.toys/ci.rb b/.toys/ci.rb
index 6e766b3..b94a82c 100644
--- a/.toys/ci.rb
+++ b/.toys/ci.rb
@@ -1,24 +1,18 @@
 # frozen_string_literal: true
 
-desc "Run all CI checks"
-
-include :exec, result_callback: :handle_result
-include :terminal
+load_git remote: "https://github.com/dazuma/toys.git",
+         path: "common-tools/ci",
+         update: 3600
 
-def handle_result result
-  if result.success?
-    puts "** #{result.name} passed\n\n", :green, :bold
-  else
-    puts "** CI terminated: #{result.name} failed!", :red, :bold
-    exit 1
-  end
-end
+desc "Run all CI checks"
 
-def run
-  ::Dir.chdir context_directory
-  exec_tool ["test"], name: "Tests"
-  exec_tool ["cucumber"], name: "Behaviors"
-  exec_tool ["rubocop"], name: "Style checker"
-  exec_tool ["yardoc"], name: "Docs generation"
-  exec_tool ["build"], name: "Gem build"
+expand("toys-ci") do |toys_ci|
+  toys_ci.only_flag = true
+  toys_ci.fail_fast_flag = true
+  toys_ci.job("Bundle update", flag: :bundle, exec: ["bundle", "update"])
+  toys_ci.job("Rubocop", flag: :rubocop, tool: ["rubocop"])
+  toys_ci.job("Tests", flag: :test, tool: ["test"])
+  toys_ci.job("Cucumber", flag: :cucumber, tool: ["cucumber"])
+  toys_ci.job("Yardoc", flag: :yard, tool: ["yardoc"])
+  toys_ci.job("Gem build", flag: :build, tool: ["build"])
 end
diff --git a/.toys/cucumber.rb b/.toys/cucumber.rb
index 7e2bf40..e0b7c1d 100644
--- a/.toys/cucumber.rb
+++ b/.toys/cucumber.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-toys_version! ">= 0.12"
+toys_version! ">= 0.15"
 
 desc "Run cucumber tests"
 
diff --git a/Gemfile b/Gemfile
index e51ac70..6254c58 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,12 +1,15 @@
 source "https://rubygems.org"
 gemspec
 
-gem "cucumber", "7.0"
-gem "google-style", "~> 1.25.1"
-gem "minitest", "~> 5.14"
-gem "minitest-focus", "~> 1.1"
-gem "minitest-rg", "~> 5.2"
-gem "rack", "~> 2.2"
-gem "redcarpet", "~> 3.5" unless ::RUBY_PLATFORM == "java"
-gem "webrick", "~> 1.7"
-gem "yard", "~> 0.9.25"
+gem "base64", "~> 0.3"
+gem "cucumber", "~> 9.2"
+gem "google-style", "~> 1.27.1"
+gem "logger", "~> 1.7"
+gem "minitest", "~> 5.25"
+gem "minitest-focus", "~> 1.4"
+gem "minitest-rg", "~> 5.3"
+gem "ostruct", "~> 0.6"
+gem "rack", "~> 3.2"
+gem "redcarpet", "~> 3.6" unless ::RUBY_PLATFORM == "java"
+gem "webrick", "~> 1.9"
+gem "yard", "~> 0.9.37"
diff --git a/cloud_events.gemspec b/cloud_events.gemspec
index 5590add..703c5f1 100644
--- a/cloud_events.gemspec
+++ b/cloud_events.gemspec
@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
-lib = ::File.expand_path "lib", __dir__
-$LOAD_PATH.unshift lib unless $LOAD_PATH.include? lib
-require "cloud_events/version"
+require_relative "lib/cloud_events/version"
 version = ::CloudEvents::VERSION
 
 ::Gem::Specification.new do |spec|
@@ -13,15 +11,15 @@ version = ::CloudEvents::VERSION
   spec.email = ["dazuma@gmail.com"]
 
   spec.summary = "Ruby SDK for CloudEvents"
-  spec.description = \
-    "The official Ruby implementation of the CloudEvents Specification." \
-    " Provides data types for events, and HTTP/JSON bindings for marshalling" \
-    " and unmarshalling event data."
+  spec.description =
+    "The official Ruby implementation of the CloudEvents Specification. " \
+    "Provides data types for events, and HTTP/JSON bindings for marshalling " \
+    "and unmarshalling event data."
   spec.homepage = "https://github.com/cloudevents/sdk-ruby"
 
   spec.files = ::Dir.glob("lib/**/*.rb") + ::Dir.glob("*.md") + [".yardopts"]
   spec.require_paths = ["lib"]
-  spec.required_ruby_version = ">= 2.5"
+  spec.required_ruby_version = ">= 2.7"
 
   if spec.respond_to? :metadata
     spec.metadata["changelog_uri"] = "https://cloudevents.github.io/sdk-ruby/v#{version}/file.CHANGELOG.html"
diff --git a/features/step_definitions/steps.rb b/features/step_definitions/steps.rb
index a5e02be..502138b 100644
--- a/features/step_definitions/steps.rb
+++ b/features/step_definitions/steps.rb
@@ -9,6 +9,11 @@
 end
 
 Given "an HTTP request" do |str|
+  # WEBrick parsing wants the lines delimited by \r\n, but the input
+  # content-length assumes \n within the body.
+  parts = str.split "\n\n"
+  parts[0].gsub! "\n", "\r\n"
+  str = "#{parts[0]}\r\n\r\n#{parts[1]}"
   webrick_request = WEBrick::HTTPRequest.new WEBrick::Config::HTTP
   webrick_request.parse StringIO.new str
   @rack_request = {}
diff --git a/lib/cloud_events/content_type.rb b/lib/cloud_events/content_type.rb
index f043ce4..e7bcc26 100644
--- a/lib/cloud_events/content_type.rb
+++ b/lib/cloud_events/content_type.rb
@@ -152,7 +152,7 @@ def consume_token str, downcase: false, error_message: nil
 
     def consume_special str, expected, error_message: nil
       raise ParseError, error_message || "Expected #{expected.inspect}" unless str.start_with? expected
-      consume_comments str[1..-1].strip
+      consume_comments str[1..].strip
     end
 
     def consume_token_or_quoted str, error_message: nil
@@ -177,7 +177,7 @@ def consume_token_or_quoted str, error_message: nil
         end
       end
       index += 1
-      str = consume_comments str[index..-1].strip
+      str = consume_comments str[index..].strip
       [arr.join, str]
     end
 
@@ -194,14 +194,14 @@ def consume_comments str
         when "\\"
           index += 2
         when "("
-          str = consume_comments str[index..-1]
+          str = consume_comments str[index..]
           index = 0
         else
           index += 1
         end
       end
       index += 1
-      consume_comments str[index..-1].strip
+      consume_comments str[index..].strip
     end
 
     def maybe_quote str
diff --git a/lib/cloud_events/event/field_interpreter.rb b/lib/cloud_events/event/field_interpreter.rb
index 08c2427..c6323be 100644
--- a/lib/cloud_events/event/field_interpreter.rb
+++ b/lib/cloud_events/event/field_interpreter.rb
@@ -30,8 +30,8 @@ def string keys, required: false, allow_empty: false
             value.freeze
             [value, value]
           else
-            raise AttributeError, "Illegal type for #{keys.first}:" \
-                                  " String expected but #{value.class} found"
+            raise AttributeError, "Illegal type for #{keys.first}: " \
+                                  "String expected but #{value.class} found"
           end
         end
       end
@@ -49,8 +49,8 @@ def uri keys, required: false
           when ::URI::Generic
             [Utils.deep_freeze(value), value.to_s.freeze]
           else
-            raise AttributeError, "Illegal type for #{keys.first}:" \
-                                  " String or URI expected but #{value.class} found"
+            raise AttributeError, "Illegal type for #{keys.first}: " \
+                                  "String or URI expected but #{value.class} found"
           end
         end
       end
@@ -70,8 +70,8 @@ def rfc3339_date_time keys, required: false
             value = value.to_datetime
             [Utils.deep_freeze(value), value.rfc3339.freeze]
           else
-            raise AttributeError, "Illegal type for #{keys.first}:" \
-                                  " String, Time, or DateTime expected but #{value.class} found"
+            raise AttributeError, "Illegal type for #{keys.first}: " \
+                                  "String, Time, or DateTime expected but #{value.class} found"
           end
         end
       end
@@ -85,8 +85,8 @@ def content_type keys, required: false
           when ContentType
             [value, value.to_s]
           else
-            raise AttributeError, "Illegal type for #{keys.first}:" \
-                                  " String, or ContentType expected but #{value.class} found"
+            raise AttributeError, "Illegal type for #{keys.first}: " \
+                                  "String, or ContentType expected but #{value.class} found"
           end
         end
       end
@@ -99,8 +99,8 @@ def spec_version keys, accept:
             value.freeze
             [value, value]
           else
-            raise AttributeError, "Illegal type for #{keys.first}:" \
-                                  " String expected but #{value.class} found"
+            raise AttributeError, "Illegal type for #{keys.first}: " \
+                                  "String expected but #{value.class} found"
           end
         end
       end
@@ -121,7 +121,7 @@ def object keys, required: false, allow_nil: false
         keys.each do |key|
           key_present = @args.key? key
           val = @args.delete key
-          value = val if allow_nil && key_present || !allow_nil && !val.nil?
+          value = val if (allow_nil && key_present) || (!allow_nil && !val.nil?)
         end
         if value == UNDEFINED
           raise AttributeError, "The #{keys.first} field is required" if required
diff --git a/lib/cloud_events/event/opaque.rb b/lib/cloud_events/event/opaque.rb
index 78f8cb2..a8f38b1 100644
--- a/lib/cloud_events/event/opaque.rb
+++ b/lib/cloud_events/event/opaque.rb
@@ -73,7 +73,7 @@ def == other
 
       ## @private
       def hash
-        @content.hash ^ @content_type.hash ^ @batch.hash
+        [@content, @content_type, @batch].hash
       end
     end
   end
diff --git a/lib/cloud_events/http_binding.rb b/lib/cloud_events/http_binding.rb
index 7fc9473..eeba6d4 100644
--- a/lib/cloud_events/http_binding.rb
+++ b/lib/cloud_events/http_binding.rb
@@ -46,10 +46,10 @@ def initialize
       end
       @event_encoders = {}
       @data_decoders = Format::Multi.new do |result|
-        result&.key?(:data) && result&.key?(:content_type) ? result : nil
+        result&.key?(:data) && result.key?(:content_type) ? result : nil
       end
       @data_encoders = Format::Multi.new do |result|
-        result&.key?(:content) && result&.key?(:content_type) ? result : nil
+        result&.key?(:content) && result.key?(:content_type) ? result : nil
       end
       text_format = TextFormat.new
       @data_decoders.formats.replace [text_format, DefaultDataFormat]
@@ -110,7 +110,7 @@ def register_formatter_methods formatter,
       @event_decoders.formats.unshift formatter if decode_event
       if encode_event
         encoders = @event_encoders[encode_event] ||= Format::Multi.new do |result|
-          result&.key?(:content) && result&.key?(:content_type) ? result : nil
+          result&.key?(:content) && result.key?(:content_type) ? result : nil
         end
         encoders.formats.unshift formatter
       end
@@ -325,7 +325,7 @@ def encode_binary_content event, legacy_data_encode: true, **format_args
     #
     def percent_decode str
       str = str.gsub(/"((?:[^"\\]|\\.)*)"/) { ::Regexp.last_match(1).gsub(/\\(.)/, '\1') }
-      decoded_str = str.gsub(/%[0-9a-fA-F]{2}/) { |m| [m[1..-1].to_i(16)].pack "C" }
+      decoded_str = str.gsub(/%[0-9a-fA-F]{2}/) { |m| [m[1..].to_i(16)].pack "C" }
       decoded_str.force_encoding ::Encoding::UTF_8
     end
 
diff --git a/lib/cloud_events/text_format.rb b/lib/cloud_events/text_format.rb
index 706b80a..8be1605 100644
--- a/lib/cloud_events/text_format.rb
+++ b/lib/cloud_events/text_format.rb
@@ -67,7 +67,7 @@ def encode_data data: UNSPECIFIED, content_type: nil, **_other_kwargs
 
     def text_content_type? content_type
       content_type&.media_type == "text" ||
-        content_type&.media_type == "application" && content_type&.subtype == "octet-stream"
+        (content_type&.media_type == "application" && content_type&.subtype == "octet-stream")
     end
   end
 end
diff --git a/test/test_http_binding.rb b/test/test_http_binding.rb
index 1e164f3..8153ee6 100644
--- a/test/test_http_binding.rb
+++ b/test/test_http_binding.rb
@@ -6,7 +6,6 @@
 require "json"
 require "stringio"
 require "uri"
-require "rack/lint"
 
 describe CloudEvents::HttpBinding do
   let(:http_binding) { CloudEvents::HttpBinding.default }
@@ -261,7 +260,7 @@ def assert_request_matches env, headers, body
     end
 
     it "decodes a binary mode rack env using an InputWrapper" do
-      my_simple_binary_mode["rack.input"] = Rack::Lint::InputWrapper.new StringIO.new my_simple_data
+      my_simple_binary_mode["rack.input"] = StringIO.new my_simple_data
       event = http_binding.decode_event my_simple_binary_mode
       assert_equal my_simple_event, event
     end