diff --git a/.rubocop.yml b/.rubocop.yml
index 815ad1c..3da05b1 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -1,6 +1,6 @@
 AllCops:
   NewCops: enable
-  TargetRubyVersion: 3.0
+  TargetRubyVersion: 3.1
   SuggestExtensions: false
   Exclude:
     - .vendor/**/*
@@ -70,6 +70,7 @@ Style/BlockDelimiters:
 Style/GlobalVars:
   Exclude:
     - ext/tree_sitter/extconf.rb
+
 Style/IfUnlessModifier:
   Enabled: false
 
diff --git a/CHANGELOG.md b/CHANGELOG.md
index f679e6c..187315d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 ## [unreleased]
 
+- Drop support for Ruby < 3.1.
 - Deprarture from the `ruby/pretty_print` API with Wadler:
   - accept `indent` which will apply to `nest` and `group` implicitly if no
     `indent:` kwarg is passed.
diff --git a/examples/oppen/oppen.rb b/examples/oppen/oppen.rb
index 709776d..692cc4a 100755
--- a/examples/oppen/oppen.rb
+++ b/examples/oppen/oppen.rb
@@ -15,6 +15,6 @@
   Oppen.eof,
 ]
 
-puts Oppen.print(tokens: tokens)
+puts Oppen.print(tokens:)
 # Hello, World!
 #   How are you doing?
diff --git a/examples/oppen_and_wadler_customization/new_line.rb b/examples/oppen_and_wadler_customization/new_line.rb
index b1ba64f..ded5c71 100755
--- a/examples/oppen_and_wadler_customization/new_line.rb
+++ b/examples/oppen_and_wadler_customization/new_line.rb
@@ -5,7 +5,7 @@
 # The new line String can be specified using the `new_line` parameter.
 new_line = '<br>'
 
-printer = Oppen::Wadler.new(indent: 2, new_line: new_line)
+printer = Oppen::Wadler.new(indent: 2, new_line:)
 
 printer.group {
   printer.text 'Hello, World!'
diff --git a/examples/oppen_and_wadler_customization/whitespace.rb b/examples/oppen_and_wadler_customization/whitespace.rb
index 2348028..d031ca4 100755
--- a/examples/oppen_and_wadler_customization/whitespace.rb
+++ b/examples/oppen_and_wadler_customization/whitespace.rb
@@ -9,7 +9,7 @@
 # to prevent trailing whitespaces can be specified using the `whitespace` parameter.
 whitespace = '**'
 
-printer = Oppen::Wadler.new(indent: 2, whitespace: whitespace)
+printer = Oppen::Wadler.new(indent: 2, whitespace:)
 
 printer.group {
   printer.text '******Hello, World!******'
diff --git a/examples/oppen_and_wadler_customization/width.rb b/examples/oppen_and_wadler_customization/width.rb
index 8c4814f..785aef3 100755
--- a/examples/oppen_and_wadler_customization/width.rb
+++ b/examples/oppen_and_wadler_customization/width.rb
@@ -6,7 +6,7 @@
 width = 5
 
 printer_width_default = Oppen::Wadler.new(indent: 2)
-printer_width_narrow = Oppen::Wadler.new(indent: 2, width: width)
+printer_width_narrow = Oppen::Wadler.new(indent: 2, width:)
 test_block = ->(printer) {
   printer.group {
     printer.text 'Hello, World!'
diff --git a/justfile b/justfile
index f7b5eb8..7993c05 100644
--- a/justfile
+++ b/justfile
@@ -45,6 +45,10 @@ gem:
 lint:
   bundle exec rubocop --config .rubocop.yml
 
+[group('lint')]
+lint-fix:
+  bundle exec rubocop --config .rubocop.yml -A
+
 [group('publish')]
 publish:
   gem -C {{PKG_OUT}} push {{GEM_FILE}}
diff --git a/lib/oppen.rb b/lib/oppen.rb
index 1a0c3c5..207c3ba 100644
--- a/lib/oppen.rb
+++ b/lib/oppen.rb
@@ -154,10 +154,10 @@ def self.oppen
     # @return [Config]
     def self.wadler(eager_print: true, trim_trailing_whitespaces: true, upsize_stack: true)
       new(
-        eager_print: eager_print,
+        eager_print:,
         indent_anchor: :current_offset,
-        trim_trailing_whitespaces: trim_trailing_whitespaces,
-        upsize_stack: upsize_stack,
+        trim_trailing_whitespaces:,
+        upsize_stack:,
       )
     end
   end
@@ -172,7 +172,7 @@ def self.wadler(eager_print: true, trim_trailing_whitespaces: true, upsize_stack
   # @return [Token::String]
   #   a new String token.
   def self.string(value, width: value.length)
-    Token::String.new(value, width: width)
+    Token::String.new(value, width:)
   end
 
   # @return [Token::Whitespace] a new Whitespace token.
@@ -196,7 +196,7 @@ def self.whitespace(value)
   #
   # @see Wadler#break example on `line_continuation`.
   def self.break(str = ' ', line_continuation: '', offset: 0, width: str.length)
-    Token::Break.new(str, width: width, line_continuation: line_continuation, offset: offset)
+    Token::Break.new(str, width:, line_continuation:, offset:)
   end
 
   # @param line_continuation [String]
@@ -209,7 +209,7 @@ def self.break(str = ' ', line_continuation: '', offset: 0, width: str.length)
   #
   # @see Wadler#break example on `line_continuation`.
   def self.line_break(line_continuation: '', offset: 0)
-    Token::LineBreak.new(line_continuation: line_continuation, offset: offset)
+    Token::LineBreak.new(line_continuation:, offset:)
   end
 
   # In a consistent group, the presence of a new line inside the group will
@@ -232,7 +232,7 @@ def self.line_break(line_continuation: '', offset: 0)
   #
   # @see Wadler#group
   def self.begin_consistent(offset: 2)
-    Token::Begin.new(break_type: :consistent, offset: offset)
+    Token::Begin.new(break_type: :consistent, offset:)
   end
 
   # In an inconsistent group, the presence of a new line inside the group will
@@ -251,7 +251,7 @@ def self.begin_consistent(offset: 2)
   #
   # @see Wadler#group
   def self.begin_inconsistent(offset: 2)
-    Token::Begin.new(break_type: :inconsistent, offset: offset)
+    Token::Begin.new(break_type: :inconsistent, offset:)
   end
 
   # @return [Token::End] a new End token.
diff --git a/lib/oppen/mixins.rb b/lib/oppen/mixins.rb
index 2f30bb5..15f56c2 100644
--- a/lib/oppen/mixins.rb
+++ b/lib/oppen/mixins.rb
@@ -24,7 +24,7 @@ def upsize_circular_array(arr, offset)
 
     # @return [String]
     def tokens_to_wadler(tokens, base_indent: 0, printer_name: 'out', width: tokens.length * 3)
-      printer = Oppen::Wadler.new(base_indent: base_indent, indent: 2, width: width)
+      printer = Oppen::Wadler.new(base_indent:, indent: 2, width:)
 
       handle_break_token = ->(token) {
         if token.offset.positive?
diff --git a/lib/oppen/print_stack.rb b/lib/oppen/print_stack.rb
index 32aadbb..606385c 100644
--- a/lib/oppen/print_stack.rb
+++ b/lib/oppen/print_stack.rb
@@ -81,7 +81,7 @@ def print(token, token_width, trim_on_break: 0)
       in Token::End
         handle_end
       in Token::Break
-        handle_break token, token_width, trim_on_break: trim_on_break
+        handle_break token, token_width, trim_on_break:
       in Token::String
         handle_string token, token_width
       end
diff --git a/lib/oppen/printer.rb b/lib/oppen/printer.rb
index 4df5bcf..b2d1bb9 100644
--- a/lib/oppen/printer.rb
+++ b/lib/oppen/printer.rb
@@ -293,7 +293,7 @@ def advance_left(token, token_width)
         end
       trim_on_break ||= 0
 
-      print_stack.print(token, token_width, trim_on_break: trim_on_break)
+      print_stack.print(token, token_width, trim_on_break:)
 
       case token
       when Token::Break
diff --git a/lib/oppen/token.rb b/lib/oppen/token.rb
index be06d90..1b9dea8 100644
--- a/lib/oppen/token.rb
+++ b/lib/oppen/token.rb
@@ -74,7 +74,7 @@ def length = 999_999
       end
 
       def initialize(line_continuation: '', offset: 0)
-        super(LineBreakString.new, line_continuation: line_continuation, offset: offset)
+        super(LineBreakString.new, line_continuation:, offset:)
       end
     end
 
diff --git a/lib/wadler/print.rb b/lib/wadler/print.rb
index 2ead099..e04620d 100644
--- a/lib/wadler/print.rb
+++ b/lib/wadler/print.rb
@@ -77,12 +77,12 @@ def add_missing_begin_and_end
     def output
       add_missing_begin_and_end
       Oppen.print(
-        tokens: tokens,
-        new_line: new_line,
-        config: config,
+        tokens:,
+        new_line:,
+        config:,
         space: space_gen,
-        out: out,
-        width: width,
+        out:,
+        width:,
       )
     end
 
@@ -327,7 +327,7 @@ def text(value, width: value.length)
         end
         tokens << Oppen.whitespace(match)
       else
-        tokens << Oppen.string(value, width: width)
+        tokens << Oppen.string(value, width:)
       end
       self
     end
@@ -345,7 +345,7 @@ def text(value, width: value.length)
     #
     # @see Wadler#break example on `line_continuation`.
     def breakable(str = ' ', line_continuation: '', width: str.length)
-      tokens << Oppen.break(str, width: width, line_continuation: line_continuation, offset: current_indent)
+      tokens << Oppen.break(str, width:, line_continuation:, offset: current_indent)
       self
     end
 
@@ -370,7 +370,7 @@ def breakable(str = ' ', line_continuation: '', width: str.length)
     #
     # @return [self]
     def break(line_continuation: '')
-      tokens << Oppen.line_break(line_continuation: line_continuation, offset: current_indent)
+      tokens << Oppen.line_break(line_continuation:, offset: current_indent)
       self
     end
 
@@ -483,11 +483,11 @@ def separate(args, sep, breakable: ' ', break_pos: :after,
               first = false
             elsif break_pos == :after
               text sep
-              breakable(breakable, line_continuation: line_continuation) if breakable && !force_break
-              self.break(line_continuation: line_continuation) if force_break
+              breakable(breakable, line_continuation:) if breakable && !force_break
+              self.break(line_continuation:) if force_break
             else
-              breakable(breakable, line_continuation: line_continuation) if breakable && !force_break
-              self.break(line_continuation: line_continuation) if force_break
+              breakable(breakable, line_continuation:) if breakable && !force_break
+              self.break(line_continuation:) if force_break
               text sep
             end
             yield(*as)
@@ -505,7 +505,7 @@ def separate(args, sep, breakable: ' ', break_pos: :after,
             body.()
           }
         }.end
-      breakable('', line_continuation: line_continuation) if !line_continuation.empty? && !break_type
+      breakable('', line_continuation:) if !line_continuation.empty? && !break_type
 
       self
     end
@@ -553,7 +553,7 @@ def surround(lft, rgt, **opts)
       text lft if lft
 
       indent = opts.fetch(:indent, @indent)
-      nest_open(indent: indent)
+      nest_open(indent:)
 
       lft_breakable = opts.fetch(:lft_breakable, '')
       lft_can_break = opts.fetch(:lft_can_break, true)
@@ -598,8 +598,8 @@ def surround(lft, rgt, **opts)
     # This is a wrapper around {separate} where `breakable: true`.
     #
     # @see [separate]
-    def lines(*args, **kwargs, &block)
-      separate(*args, **kwargs.merge(force_break: true), &block)
+    def lines(*args, **kwargs, &)
+      separate(*args, **kwargs.merge(force_break: true), &)
     end
 
     # Concatenates args.
@@ -607,8 +607,8 @@ def lines(*args, **kwargs, &block)
     # This is a wrapper around {separate} where `breakable: false`.
     #
     # @see [separate]
-    def concat *args, **kwargs, &block
-      separate(*args, **kwargs.merge(breakable: false), &block)
+    def concat(*args, **kwargs, &)
+      separate(*args, **kwargs.merge(breakable: false), &)
     end
 
     # @!endgroup
@@ -634,15 +634,15 @@ def angles(padding: '', **kwargs, &block)
     # {surround} with `< >`. New lines cannot appear after and before the delimiters.
     #
     # @return [self]
-    def angles_break_both(**kwargs, &block)
-      angles(**kwargs.merge(lft_force_break: true, rgt_force_break: true), &block)
+    def angles_break_both(**kwargs, &)
+      angles(**kwargs.merge(lft_force_break: true, rgt_force_break: true), &)
     end
 
     # {surround} with `< >`. New lines will appear after and before the delimiters.
     #
     # @return [self]
-    def angles_break_none(**kwargs, &block)
-      angles(**kwargs.merge(lft_can_break: false, rgt_can_break: false), &block)
+    def angles_break_none(**kwargs, &)
+      angles(**kwargs.merge(lft_can_break: false, rgt_can_break: false), &)
     end
 
     # {surround} with `{ }`. New lines can appear after and before the delimiters.
@@ -662,15 +662,15 @@ def braces(padding: '', **kwargs, &block)
     # {surround} with `{ }`. New lines cannot appear after and before the delimiters.
     #
     # @return [self]
-    def braces_break_both(**kwargs, &block)
-      braces(**kwargs.merge(lft_force_break: true, rgt_force_break: true), &block)
+    def braces_break_both(**kwargs, &)
+      braces(**kwargs.merge(lft_force_break: true, rgt_force_break: true), &)
     end
 
     # {surround} with `{ }`. New lines will appear after and before the delimiters.
     #
     # @return [self]
-    def braces_break_none(**kwargs, &block)
-      braces(**kwargs.merge(lft_can_break: false, rgt_can_break: false), &block)
+    def braces_break_none(**kwargs, &)
+      braces(**kwargs.merge(lft_can_break: false, rgt_can_break: false), &)
     end
 
     # {surround} with `[ ]`. New lines can appear after and before the delimiters.
@@ -690,15 +690,15 @@ def brackets(padding: '', **kwargs, &block)
     # {surround} with `[ ]`. New lines cannot appear after and before the delimiters.
     #
     # @return [self]
-    def brackets_break_both(**kwargs, &block)
-      brackets(**kwargs.merge(lft_force_break: true, rgt_force_break: true), &block)
+    def brackets_break_both(**kwargs, &)
+      brackets(**kwargs.merge(lft_force_break: true, rgt_force_break: true), &)
     end
 
     # {surround} with `[ ]`. New lines will appear after and before the delimiters.
     #
     # @return [self]
-    def brackets_break_none(**kwargs, &block)
-      brackets(**kwargs.merge(lft_can_break: false, rgt_can_break: false), &block)
+    def brackets_break_none(**kwargs, &)
+      brackets(**kwargs.merge(lft_can_break: false, rgt_can_break: false), &)
     end
 
     # {surround} with `( )`. New lines can appear after and before the delimiters.
@@ -718,39 +718,39 @@ def parens(padding: '', **kwargs, &block)
     # {surround} with `( )`. New lines cannot appear after and before the delimiters.
     #
     # @return [self]
-    def parens_break_both(**kwargs, &block)
-      parens(**kwargs.merge(lft_force_break: true, rgt_force_break: true), &block)
+    def parens_break_both(**kwargs, &)
+      parens(**kwargs.merge(lft_force_break: true, rgt_force_break: true), &)
     end
 
     # {surround} with `( )`. New lines will appear after and before the delimiters.
     #
     # @return [self]
-    def parens_break_none(**kwargs, &block)
-      parens(**kwargs.merge(lft_can_break: false, rgt_can_break: false), &block)
+    def parens_break_none(**kwargs, &)
+      parens(**kwargs.merge(lft_can_break: false, rgt_can_break: false), &)
     end
 
     # {surround} with `` ` ` ``. New lines cannot appear after and before the delimiters
     # unless you specify it with `rgt_can_break` and `lft_can_break`.
     #
     # @return [self]
-    def backticks(**kwargs, &block)
-      surround('`', '`', lft_can_break: false, rgt_can_break: false, **kwargs, &block)
+    def backticks(**kwargs, &)
+      surround('`', '`', lft_can_break: false, rgt_can_break: false, **kwargs, &)
     end
 
     # {surround} with `" "`. New lines cannot appear after and before the delimiters
     # unless you specify it with `rgt_can_break` and `lft_can_break`.
     #
     # @return [self]
-    def quote_double(**kwargs, &block)
-      surround('"', '"', lft_can_break: false, rgt_can_break: false, **kwargs, &block)
+    def quote_double(**kwargs, &)
+      surround('"', '"', lft_can_break: false, rgt_can_break: false, **kwargs, &)
     end
 
     # {surround} with `' '`. New lines cannot appear after and before the delimiters
     # unless you specify it with `rgt_can_break` and `lft_can_break`.
     #
     # @return [self]
-    def quote_single(**kwargs, &block)
-      surround("'", "'", lft_can_break: false, rgt_can_break: false, **kwargs, &block)
+    def quote_single(**kwargs, &)
+      surround("'", "'", lft_can_break: false, rgt_can_break: false, **kwargs, &)
     end
 
     # Open a consistent group.
diff --git a/oppen.gemspec b/oppen.gemspec
index adc25ba..4c79333 100644
--- a/oppen.gemspec
+++ b/oppen.gemspec
@@ -19,5 +19,5 @@ Gem::Specification.new do |spec|
 
   spec.files                 = Dir['lib/**/*', 'LICENSE', 'README.md']
   spec.require_paths         = ['lib']
-  spec.required_ruby_version = Gem::Requirement.new('>= 3.0')
+  spec.required_ruby_version = Gem::Requirement.new('>= 3.1')
 end
diff --git a/test/customization_test.rb b/test/customization_test.rb
index 33400bf..87798fd 100644
--- a/test/customization_test.rb
+++ b/test/customization_test.rb
@@ -224,7 +224,7 @@ def nest_delimiter_build_output(printer, delim)
         printer.text 'foo()'
       }
       printer.break
-      printer.nest(delim: delim, indent: 2) {
+      printer.nest(delim:, indent: 2) {
         printer.group {
           printer.text 'Hello'
           printer.breakable(', ')
@@ -304,7 +304,7 @@ def group_delimiter_build_output(printer, delim)
         printer.breakable
         printer.text 'foo()'
       }
-      printer.group(delim: delim, indent: 2) {
+      printer.group(delim:, indent: 2) {
         printer.group {
           printer.break
           printer.text 'Hello'
@@ -385,12 +385,12 @@ def line_continuation_build_output(printer, break_type = :consistent,
       printer.group(break_type, indent: 2) {
         printer.breakable ''
         printer.text '1'
-        printer.breakable ', ', line_continuation: line_continuation
+        printer.breakable(', ', line_continuation:)
         printer.text '2'
-        printer.breakable ', ', line_continuation: line_continuation
+        printer.breakable(', ', line_continuation:)
         printer.text '3'
       }
-      printer.breakable '', line_continuation: line_continuation
+      printer.breakable('', line_continuation:)
       printer.text ']'
     }
   end
diff --git a/test/indent_anchor_test.rb b/test/indent_anchor_test.rb
index e9929ac..f5a7a33 100644
--- a/test/indent_anchor_test.rb
+++ b/test/indent_anchor_test.rb
@@ -5,11 +5,11 @@
 require_relative 'lib'
 
 def check_difference_oppen_wadler(width, expected_oppen, expected_wadler, builder_block)
-  printer = Oppen::Wadler.new(width: width, config: Oppen::Config.oppen)
+  printer = Oppen::Wadler.new(width:, config: Oppen::Config.oppen)
   builder_block.(printer)
   _(printer.output).must_equal expected_oppen, 'Oppen failed the test'
 
-  printer = Oppen::Wadler.new(width: width, config: Oppen::Config.wadler)
+  printer = Oppen::Wadler.new(width:, config: Oppen::Config.wadler)
   builder_block.(printer)
   _(printer.output).must_equal expected_wadler, 'Wadler failed the test'
 end
diff --git a/test/lib.rb b/test/lib.rb
index 6cda1dc..bcd550a 100644
--- a/test/lib.rb
+++ b/test/lib.rb
@@ -41,7 +41,7 @@ def break
 end
 
 def assert_wadler(width, expected, builder_block, indent: 0)
-  printer = Oppen::Wadler.new(indent: indent, width: width)
+  printer = Oppen::Wadler.new(indent:, width:)
   builder_block.(printer)
   _(printer.output).must_equal expected, 'Oppen failed the test'
 end
diff --git a/test/trim_trailing_whitespaces_test.rb b/test/trim_trailing_whitespaces_test.rb
index b605025..6dcedeb 100644
--- a/test/trim_trailing_whitespaces_test.rb
+++ b/test/trim_trailing_whitespaces_test.rb
@@ -59,7 +59,7 @@
       },
     ].each do |test|
       it test[:title] do
-        printer = Oppen::Wadler.new(width: 5, whitespace: whitespace)
+        printer = Oppen::Wadler.new(width: 5, whitespace:)
         test[:block].(printer)
         _(printer.output).must_equal test[:expected]
       end
@@ -191,11 +191,11 @@
       },
     ].each do |test|
       it test[:title] do
-        printer = Oppen::Wadler.new(width: 5, whitespace: whitespace)
+        printer = Oppen::Wadler.new(width: 5, whitespace:)
         test[:block].(printer)
         _(printer.output).must_equal test[:expected]
 
-        printer_no_trailing = Oppen::Wadler.new(width: 5, whitespace: whitespace)
+        printer_no_trailing = Oppen::Wadler.new(width: 5, whitespace:)
         test[:block].(printer_no_trailing, false)
         _(printer_no_trailing.output).must_equal test[:expected]
       end