diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 03b2cce..4a7f98d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -14,10 +14,11 @@ on:
 jobs:
   rspec:
     runs-on: ubuntu-latest
+    if: ${{ !contains(github.event.head_commit.message, 'skip-ci') }}
     strategy:
       fail-fast: false
       matrix:
-        ruby-version: ['3.1', '3.2', '3.3', '3.4']
+        ruby-version: ['3.1', '3.2', '3.3', '3.4', '4.0']
 
     steps:
     - uses: actions/checkout@v4
@@ -35,6 +36,7 @@ jobs:
 
   rspec_each:
     runs-on: ubuntu-latest
+    if: ${{ !contains(github.event.head_commit.message, 'skip-ci') }}
 
     steps:
     - uses: actions/checkout@v4
@@ -52,6 +54,7 @@ jobs:
 
   rubocop:
     runs-on: ubuntu-latest
+    if: ${{ !contains(github.event.head_commit.message, 'skip-ci') }}
 
     steps:
     - uses: actions/checkout@v4
diff --git a/.github/workflows/deploy-pages.yml b/.github/workflows/deploy-pages.yml
index 85127b0..f8cc49c 100644
--- a/.github/workflows/deploy-pages.yml
+++ b/.github/workflows/deploy-pages.yml
@@ -27,7 +27,7 @@ jobs:
       - name: Set up Ruby
         uses: ruby/setup-ruby@v1
         with:
-          ruby-version: '3.3'
+          ruby-version: '3.4'
           bundler-cache: true # runs 'bundle install' and caches installed gems automatically
 
       - name: Setup Pages
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index d44722d..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,16 +0,0 @@
-# Build Options
-language: ruby
-rvm:
-  - 2.6.8
-  - 2.7.4
-  - 3.0.2
-before_install:
-  - sudo apt-get update && sudo apt-get install apt-transport-https ca-certificates -y && sudo update-ca-certificates
-before_script:
-  - cp .rspec.example .rspec
-script:
-  - bundle exec thor ci:steps
-
-# Travis-CI Configuration
-cache: bundler
-dist: focal
diff --git a/Gemfile b/Gemfile
index 9cee559..deac34a 100644
--- a/Gemfile
+++ b/Gemfile
@@ -10,10 +10,10 @@ group :development, :test do
   gem 'byebug', '~> 11.1'
 
   gem 'rspec', '~> 3.13'
-  gem 'rspec-sleeping_king_studios', '~> 2.8.0'
+  gem 'rspec-sleeping_king_studios', '~> 2.8', '>= 2.8.3'
 
-  gem 'rubocop',       '~> 1.75'
-  gem 'rubocop-rspec', '~> 3.6'
+  gem 'rubocop',       '~> 1.82'
+  gem 'rubocop-rspec', '~> 3.8'
 
   gem 'simplecov', '~> 0.22'
 end
@@ -25,7 +25,9 @@ group :docs do
   # Use Kramdown to parse GFM-dialect Markdown.
   gem 'kramdown-parser-gfm', '~> 1.1'
 
-  gem 'sleeping_king_studios-docs', '~> 0.1'
+  gem 'sleeping_king_studios-docs',
+    branch: 'chore/ruby-4-0',
+    git:    'https://github.com/sleepingkingstudios/sleeping_king_studios-docs'
 
   # Use Webrick as local content server.
   gem 'webrick', '~> 1.8'
diff --git a/cuprum.gemspec b/cuprum.gemspec
index 8003d93..176994f 100644
--- a/cuprum.gemspec
+++ b/cuprum.gemspec
@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
-$LOAD_PATH << './lib'
-
-require 'cuprum/version'
+require_relative 'lib/cuprum/version'
 
 Gem::Specification.new do |gem|
   gem.name        = 'cuprum'
@@ -27,9 +25,9 @@ Gem::Specification.new do |gem|
     'rubygems_mfa_required' => 'true'
   }
 
-  gem.required_ruby_version = '~> 3.1'
+  gem.required_ruby_version = ['>= 3.1', '< 5']
   gem.require_path = 'lib'
   gem.files        = Dir['lib/**/*.rb', 'LICENSE', '*.md']
 
-  gem.add_runtime_dependency 'sleeping_king_studios-tools', '~> 1.2'
+  gem.add_runtime_dependency 'sleeping_king_studios-tools', '~> 1.2', '>= 1.2.1'
 end
diff --git a/docs/versions/1.1/index.md b/docs/versions/1.1/index.md
index 261b310..35f976c 100644
--- a/docs/versions/1.1/index.md
+++ b/docs/versions/1.1/index.md
@@ -38,3 +38,5 @@ Cuprum defines the following core components:
   Define handling for results based on `#status`, `#error`, and `#value`.
 
 For a full list of defined classes and objects, see [Reference](./reference).
+
+{% include breadcrumbs.md %}
diff --git a/docs/versions/1.1/reference/index.md b/docs/versions/1.1/reference/index.md
new file mode 100644
index 0000000..cb3d6a2
--- /dev/null
+++ b/docs/versions/1.1/reference/index.md
@@ -0,0 +1,18 @@
+---
+breadcrumbs:
+  - name: Documentation
+    path: '../../../'
+  - name: Versions
+    path: '../../'
+  - name: '1.1'
+    path: '../'
+version: '1.1'
+---
+
+{% assign root_namespace = site.namespaces | where: "version", page.version | first %}
+
+# Cuprum Reference
+
+{% include reference/namespace.md label=false namespace=root_namespace %}
+
+{% include breadcrumbs.md %}
diff --git a/docs/versions/1.2/index.md b/docs/versions/1.2/index.md
index 419d070..40ccddf 100644
--- a/docs/versions/1.2/index.md
+++ b/docs/versions/1.2/index.md
@@ -38,3 +38,5 @@ Cuprum defines the following core components:
   Define handling for results based on `#status`, `#error`, and `#value`.
 
 For a full list of defined classes and objects, see [Reference](./reference).
+
+{% include breadcrumbs.md %}
diff --git a/docs/versions/1.2/reference/index.md b/docs/versions/1.2/reference/index.md
new file mode 100644
index 0000000..7289e88
--- /dev/null
+++ b/docs/versions/1.2/reference/index.md
@@ -0,0 +1,18 @@
+---
+breadcrumbs:
+  - name: Documentation
+    path: '../../../'
+  - name: Versions
+    path: '../../'
+  - name: '1.2'
+    path: '../'
+version: '1.2'
+---
+
+{% assign root_namespace = site.namespaces | where: "version", page.version | first %}
+
+# Cuprum Reference
+
+{% include reference/namespace.md label=false namespace=root_namespace %}
+
+{% include breadcrumbs.md %}
diff --git a/docs/versions/1.3/index.md b/docs/versions/1.3/index.md
index 0a86d1a..5ce8d4a 100644
--- a/docs/versions/1.3/index.md
+++ b/docs/versions/1.3/index.md
@@ -38,3 +38,5 @@ Cuprum defines the following core components:
   Define handling for results based on `#status`, `#error`, and `#value`.
 
 For a full list of defined classes and objects, see [Reference](./reference).
+
+{% include breadcrumbs.md %}
diff --git a/docs/versions/1.3/reference/index.md b/docs/versions/1.3/reference/index.md
new file mode 100644
index 0000000..b1ea37f
--- /dev/null
+++ b/docs/versions/1.3/reference/index.md
@@ -0,0 +1,18 @@
+---
+breadcrumbs:
+  - name: Documentation
+    path: '../../../'
+  - name: Versions
+    path: '../../'
+  - name: '1.3'
+    path: '../'
+version: '1.3'
+---
+
+{% assign root_namespace = site.namespaces | where: "version", page.version | first %}
+
+# Cuprum Reference
+
+{% include reference/namespace.md label=false namespace=root_namespace %}
+
+{% include breadcrumbs.md %}
diff --git a/lib/cuprum/result.rb b/lib/cuprum/result.rb
index 5c9d59f..b7a3376 100644
--- a/lib/cuprum/result.rb
+++ b/lib/cuprum/result.rb
@@ -77,7 +77,7 @@ def defined_statuses
       self.class::STATUSES
     end
 
-    def deprecated_compare(other)
+    def deprecated_compare(other) # rubocop:disable Naming/PredicateMethod
       unless %i[value status error].all? { |sym| other.respond_to?(sym) }
         return false
       end
diff --git a/lib/cuprum/rspec/be_a_result_matcher.rb b/lib/cuprum/rspec/be_a_result_matcher.rb
index 3cc4d9b..730d15f 100644
--- a/lib/cuprum/rspec/be_a_result_matcher.rb
+++ b/lib/cuprum/rspec/be_a_result_matcher.rb
@@ -104,7 +104,7 @@ def description
     # @param actual [Object] the actual object to match.
     #
     # @return [Boolean] false if the actual object is a result; otherwise true.
-    def does_not_match?(actual) # rubocop:disable Naming/PredicateName
+    def does_not_match?(actual) # rubocop:disable Naming/PredicatePrefix
       @actual = actual
 
       raise ArgumentError, negated_matcher_warning if expected_properties?
@@ -210,7 +210,7 @@ def actual_is_uncalled_operation?
       result.error.is_a?(Cuprum::Errors::OperationNotCalled)
     end
 
-    def compare_items(expected, actual)
+    def compare_items(expected, actual) # rubocop:disable Naming/PredicateMethod
       return expected.matches?(actual) if expected.respond_to?(:matches?)
 
       expected == actual
diff --git a/spec/cuprum/result/with_custom_status_spec.rb b/spec/cuprum/result/with_custom_status_spec.rb
index aaf3780..bd43eba 100644
--- a/spec/cuprum/result/with_custom_status_spec.rb
+++ b/spec/cuprum/result/with_custom_status_spec.rb
@@ -105,7 +105,7 @@
         'status: :halted'  => :halted,
         'status: :success' => :success
       }
-      default_scenarios = {
+      default_scenarios = { # rubocop:disable RSpec/LeakyLocalVariable
         value:  value_scenarios,
         error:  error_scenarios,
         status: status_scenarios
@@ -121,7 +121,7 @@
         default_scenarios
 
       wrap_context 'when the result has a value' do
-        all_scenarios = {
+        all_scenarios = { # rubocop:disable RSpec/LeakyLocalVariable
           value:  value_scenarios.merge('a matching value' => 'returned value'),
           error:  error_scenarios,
           status: status_scenarios.merge('status: :halted' => :halted)
@@ -149,7 +149,7 @@
       end
 
       wrap_context 'when the result has an error' do
-        all_scenarios = {
+        all_scenarios = { # rubocop:disable RSpec/LeakyLocalVariable
           value:  value_scenarios,
           error:  error_scenarios.merge(
             'a matching error' => Cuprum::Error.new(
@@ -184,7 +184,7 @@
         include_context 'when the result has a value'
         include_context 'when the result has an error'
 
-        all_scenarios = {
+        all_scenarios = { # rubocop:disable RSpec/LeakyLocalVariable
           value:  value_scenarios.merge('a matching value' => 'returned value'),
           error:  error_scenarios.merge(
             'a matching error' => Cuprum::Error.new(
diff --git a/spec/cuprum/result_spec.rb b/spec/cuprum/result_spec.rb
index 53f46ec..b19bf25 100644
--- a/spec/cuprum/result_spec.rb
+++ b/spec/cuprum/result_spec.rb
@@ -83,7 +83,7 @@
       'status: :failure' => :failure,
       'status: :success' => :success
     }
-    default_scenarios = {
+    default_scenarios = { # rubocop:disable RSpec/LeakyLocalVariable
       value:  value_scenarios,
       error:  error_scenarios,
       status: status_scenarios
@@ -99,7 +99,7 @@
       default_scenarios
 
     wrap_context 'when the result has a value' do
-      all_scenarios = {
+      all_scenarios = { # rubocop:disable RSpec/LeakyLocalVariable
         value:  value_scenarios.merge('a matching value' => 'returned value'),
         error:  error_scenarios,
         status: status_scenarios
@@ -122,7 +122,7 @@
     end
 
     wrap_context 'when the result has an error' do
-      all_scenarios = {
+      all_scenarios = { # rubocop:disable RSpec/LeakyLocalVariable
         value:  value_scenarios,
         error:  error_scenarios.merge(
           'a matching error' => Cuprum::Error.new(
@@ -152,7 +152,7 @@
       include_context 'when the result has a value'
       include_context 'when the result has an error'
 
-      all_scenarios = {
+      all_scenarios = { # rubocop:disable RSpec/LeakyLocalVariable
         value:  value_scenarios.merge('a matching value' => 'returned value'),
         error:  error_scenarios.merge(
           'a matching error' => Cuprum::Error.new(