diff --git a/.github/workflows/rubocop.yml b/.github/workflows/rubocop.yml
index d66266dd..ad8ef10e 100644
--- a/.github/workflows/rubocop.yml
+++ b/.github/workflows/rubocop.yml
@@ -8,11 +8,11 @@ jobs:
     env:
       BUNDLE_WITHOUT: development
     steps:
-    - uses: actions/checkout@v3
-    - name: Set up Ruby 2.6
+    - uses: actions/checkout@v5
+    - name: Set up Ruby 3.4
       uses: ruby/setup-ruby@v1
       with:
-        ruby-version: 2.6
+        ruby-version: 3.4
         bundler-cache: true # runs 'bundle install' and caches installed gems automatically
     - name: Run RuboCop
       run: bundle exec rubocop
diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index 02cfbae1..9a0c4b62 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -1,18 +1,11 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config`
-# on 2022-05-30 13:48:55 UTC using RuboCop version 1.30.0.
+# on 2025-09-23 00:00:00 UTC using RuboCop version 1.80.2.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
 # versions of RuboCop, may require this file to be generated again.
 
-# Offense count: 3
-# This cop supports safe autocorrection (--autocorrect).
-Layout/HeredocIndentation:
-  Exclude:
-    - 'support/ruby_enc_to_mysql.rb'
-    - 'tasks/compile.rake'
-
 # Offense count: 2
 # Configuration parameters: AllowedMethods.
 # AllowedMethods: enums
@@ -22,23 +15,24 @@ Lint/ConstantDefinitionInBlock:
     - 'tasks/rspec.rake'
 
 # Offense count: 1
+# Configuration parameters: AllowedParentClasses.
 Lint/MissingSuper:
   Exclude:
     - 'lib/mysql2/em.rb'
 
 # Offense count: 2
-# Configuration parameters: IgnoredMethods, CountRepeatedAttributes.
+# Configuration parameters: AllowedMethods, AllowedPatterns, CountRepeatedAttributes.
 Metrics/AbcSize:
-  Max: 94
+  Max: 89
 
 # Offense count: 34
-# Configuration parameters: CountComments, CountAsOne, ExcludedMethods, IgnoredMethods.
-# IgnoredMethods: refine
+# Configuration parameters: CountComments, CountAsOne, AllowedMethods, AllowedPatterns.
+# AllowedMethods: refine
 Metrics/BlockLength:
-  Max: 592
+  Max: 477
 
 # Offense count: 1
-# Configuration parameters: CountBlocks.
+# Configuration parameters: CountBlocks, CountModifierForms.
 Metrics/BlockNesting:
   Max: 5
 
@@ -48,34 +42,28 @@ Metrics/ClassLength:
   Max: 141
 
 # Offense count: 3
-# Configuration parameters: IgnoredMethods.
+# Configuration parameters: AllowedMethods, AllowedPatterns.
 Metrics/CyclomaticComplexity:
-  Max: 34
+  Max: 32
 
 # Offense count: 6
-# Configuration parameters: CountComments, CountAsOne, ExcludedMethods, IgnoredMethods.
+# Configuration parameters: CountComments, CountAsOne, AllowedMethods, AllowedPatterns.
 Metrics/MethodLength:
-  Max: 57
+  Max: 52
 
 # Offense count: 2
-# Configuration parameters: IgnoredMethods.
+# Configuration parameters: AllowedMethods, AllowedPatterns.
 Metrics/PerceivedComplexity:
-  Max: 32
+  Max: 30
 
 # Offense count: 2
 # Configuration parameters: ForbiddenDelimiters.
-# ForbiddenDelimiters: (?-mix:(^|\s)(EO[A-Z]{1}|END)(\s|$))
+# ForbiddenDelimiters: (?i-mx:(^|\s)(EO[A-Z]{1}|END)(\s|$))
 Naming/HeredocDelimiterNaming:
   Exclude:
     - 'tasks/compile.rake'
 
-# Offense count: 1
-# This cop supports unsafe autocorrection (--autocorrect-all).
-Style/CaseLikeIf:
-  Exclude:
-    - 'ext/mysql2/extconf.rb'
-
-# Offense count: 8
+# Offense count: 9
 # Configuration parameters: AllowedConstants.
 Style/Documentation:
   Exclude:
@@ -100,13 +88,13 @@ Style/ExpandPathArguments:
     - 'support/mysql_enc_to_ruby.rb'
     - 'tasks/compile.rake'
 
-# Offense count: 15
+# Offense count: 17
 # Configuration parameters: AllowedVariables.
 Style/GlobalVars:
   Exclude:
     - 'ext/mysql2/extconf.rb'
 
-# Offense count: 8
+# Offense count: 7
 # This cop supports safe autocorrection (--autocorrect).
 Style/IfUnlessModifier:
   Exclude:
@@ -116,14 +104,14 @@ Style/IfUnlessModifier:
 
 # Offense count: 1
 # This cop supports safe autocorrection (--autocorrect).
-# Configuration parameters: AllowMethodComparison.
+# Configuration parameters: AllowMethodComparison, ComparisonsThreshold.
 Style/MultipleComparison:
   Exclude:
     - 'lib/mysql2/client.rb'
 
-# Offense count: 18
+# Offense count: 24
 # This cop supports safe autocorrection (--autocorrect).
-# Configuration parameters: Strict, AllowedNumbers.
+# Configuration parameters: Strict, AllowedNumbers, AllowedPatterns.
 Style/NumericLiterals:
   MinDigits: 20
 
@@ -144,7 +132,7 @@ Style/StringConcatenation:
     - 'lib/mysql2/client.rb'
     - 'tasks/compile.rake'
 
-# Offense count: 782
+# Offense count: 805
 # This cop supports safe autocorrection (--autocorrect).
 # Configuration parameters: EnforcedStyle, ConsistentQuotesInMultiline.
 # SupportedStyles: single_quotes, double_quotes
@@ -159,9 +147,9 @@ Style/WordArray:
   EnforcedStyle: percent
   MinSize: 4
 
-# Offense count: 32
+# Offense count: 43
 # This cop supports safe autocorrection (--autocorrect).
-# Configuration parameters: AllowHeredoc, AllowURI, URISchemes, IgnoreCopDirectives, AllowedPatterns, IgnoredPatterns.
+# Configuration parameters: AllowHeredoc, AllowURI, AllowQualifiedName, URISchemes, IgnoreCopDirectives, AllowedPatterns, SplitStrings.
 # URISchemes: http, https
 Layout/LineLength:
   Max: 232
diff --git a/Gemfile b/Gemfile
index abf41562..b8335fd2 100644
--- a/Gemfile
+++ b/Gemfile
@@ -16,9 +16,7 @@ group :test do
   gem 'eventmachine' unless RUBY_PLATFORM =~ /mswin|mingw/
   gem 'rspec', '~> 3.2'
 
-  # https://github.com/bbatsov/rubocop/pull/4789
-  # 1.51 is the last version supporting Ruby 2.6
-  gem 'rubocop', '>= 1.30.1', '< 1.51' if Gem::Version.new(RUBY_VERSION) >= Gem::Version.new('2.6')
+  gem 'rubocop'
 end
 
 group :benchmarks, optional: true do
diff --git a/ext/mysql2/extconf.rb b/ext/mysql2/extconf.rb
index 147b998b..44914729 100644
--- a/ext/mysql2/extconf.rb
+++ b/ext/mysql2/extconf.rb
@@ -113,7 +113,7 @@ def add_ssl_defines(header)
   warn "-----\nUsing --with-mysql-dir=#{File.dirname inc}\n-----"
   rpath_dir = lib
   have_library('mysqlclient')
-elsif (mc = (with_config('mysql-config') || Dir[GLOB].first))
+elsif (mc = with_config('mysql-config') || Dir[GLOB].first)
   # If the user has provided a --with-mysql-config argument, we must respect it or fail.
   # If the user gave --with-mysql-config with no argument means we should try to find it.
   mc = Dir[GLOB].first if mc == true