diff --git a/ruby/.rubocop.yml b/ruby/.rubocop.yml
index 9f8fefc1..5fb4e130 100644
--- a/ruby/.rubocop.yml
+++ b/ruby/.rubocop.yml
@@ -1,10 +1,15 @@
+AllCops:
+  TargetRubyVersion: 2.7
+  SuggestExtensions: false
+  NewCops: enable
+
 Style/Encoding:
   Enabled: false
 
 Layout/EndOfLine:
   EnforcedStyle: lf
 
-Metrics/LineLength:
+Layout/LineLength:
   Max: 180
 
 Metrics/ClassLength:
@@ -24,3 +29,6 @@ Metrics/AbcSize:
 
 Metrics/ParameterLists:
   Max: 7
+
+Gemspec/RequiredRubyVersion:
+  Enabled: false
diff --git a/ruby/.ruby-version b/ruby/.ruby-version
index 57cf282e..37c2961c 100644
--- a/ruby/.ruby-version
+++ b/ruby/.ruby-version
@@ -1 +1 @@
-2.6.5
+2.7.2
diff --git a/ruby/Gemfile.lock b/ruby/Gemfile.lock
index a23ddbf0..63e1fcde 100644
--- a/ruby/Gemfile.lock
+++ b/ruby/Gemfile.lock
@@ -8,45 +8,50 @@ GEM
   remote: https://rubygems.org/
   specs:
     asciidoctor (2.0.11)
-    ast (2.4.1)
-    diff-lcs (1.3)
-    jaro_winkler (1.5.4)
-    parallel (1.19.1)
-    parser (2.7.1.3)
-      ast (~> 2.4.0)
+    ast (2.4.2)
+    diff-lcs (1.4.4)
+    parallel (1.21.0)
+    parser (3.0.2.0)
+      ast (~> 2.4.1)
     rainbow (3.0.0)
-    rake (12.3.3)
-    rspec (3.8.0)
-      rspec-core (~> 3.8.0)
-      rspec-expectations (~> 3.8.0)
-      rspec-mocks (~> 3.8.0)
-    rspec-core (3.8.2)
-      rspec-support (~> 3.8.0)
-    rspec-expectations (3.8.6)
+    rake (13.0.6)
+    regexp_parser (2.1.1)
+    rexml (3.2.5)
+    rspec (3.10.0)
+      rspec-core (~> 3.10.0)
+      rspec-expectations (~> 3.10.0)
+      rspec-mocks (~> 3.10.0)
+    rspec-core (3.10.1)
+      rspec-support (~> 3.10.0)
+    rspec-expectations (3.10.1)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.8.0)
-    rspec-mocks (3.8.2)
+      rspec-support (~> 3.10.0)
+    rspec-mocks (3.10.2)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.8.0)
-    rspec-support (3.8.3)
-    rubocop (0.74.0)
-      jaro_winkler (~> 1.5.1)
+      rspec-support (~> 3.10.0)
+    rspec-support (3.10.2)
+    rubocop (1.21.0)
       parallel (~> 1.10)
-      parser (>= 2.6)
+      parser (>= 3.0.0.0)
       rainbow (>= 2.2.2, < 4.0)
+      regexp_parser (>= 1.8, < 3.0)
+      rexml
+      rubocop-ast (>= 1.9.1, < 2.0)
       ruby-progressbar (~> 1.7)
-      unicode-display_width (>= 1.4.0, < 1.7)
-    ruby-progressbar (1.10.1)
-    unicode-display_width (1.6.1)
+      unicode-display_width (>= 1.4.0, < 3.0)
+    rubocop-ast (1.11.0)
+      parser (>= 3.0.1.1)
+    ruby-progressbar (1.11.0)
+    unicode-display_width (2.0.0)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
   asciidoctor-kroki!
-  rake (~> 12.3.2)
-  rspec (~> 3.8.0)
-  rubocop (~> 0.74.0)
+  rake (~> 13.0.6)
+  rspec (~> 3.10.0)
+  rubocop (~> 1.21)
 
 BUNDLED WITH
    2.2.17
diff --git a/ruby/asciidoctor-kroki.gemspec b/ruby/asciidoctor-kroki.gemspec
index 3ab96941..08b16150 100644
--- a/ruby/asciidoctor-kroki.gemspec
+++ b/ruby/asciidoctor-kroki.gemspec
@@ -20,7 +20,7 @@ Gem::Specification.new do |s|
 
   s.add_runtime_dependency 'asciidoctor', '~> 2.0'
 
-  s.add_development_dependency 'rake', '~> 12.3.2'
-  s.add_development_dependency 'rspec', '~> 3.8.0'
-  s.add_development_dependency 'rubocop', '~> 0.74.0'
+  s.add_development_dependency 'rake', '~> 13.0.6'
+  s.add_development_dependency 'rspec', '~> 3.10.0'
+  s.add_development_dependency 'rubocop', '~> 1.21'
 end
diff --git a/ruby/lib/asciidoctor/extensions/asciidoctor_kroki/extension.rb b/ruby/lib/asciidoctor/extensions/asciidoctor_kroki/extension.rb
index 4473ab14..30552eb5 100644
--- a/ruby/lib/asciidoctor/extensions/asciidoctor_kroki/extension.rb
+++ b/ruby/lib/asciidoctor/extensions/asciidoctor_kroki/extension.rb
@@ -67,7 +67,7 @@ def process(parent, target, attrs)
 
       begin
         diagram_text = read(path)
-      rescue => e # rubocop:disable RescueStandardError
+      rescue => e # rubocop:disable Style/RescueStandardError
         logger.error "Failed to read #{diagram_type} file: #{path}. #{e}."
         return create_block(parent, 'paragraph', unresolved_block_macro_message(diagram_type, path), {})
       end
@@ -89,7 +89,7 @@ def read_allowed?(_target)
     def read(target)
       if target.start_with?('http://') || target.start_with?('https://')
         require 'open-uri'
-        URI.open(target, &:read)
+        ::OpenURI.open_uri(target, &:read)
       else
         File.open(target, &:read)
       end
@@ -135,6 +135,7 @@ class KrokiProcessor
     TEXT_FORMATS = %w[txt atxt utxt].freeze
 
     class << self
+      # rubocop:disable Metrics/AbcSize
       def process(processor, parent, attrs, diagram_type, diagram_text, logger)
         doc = parent.document
         diagram_text = prepend_plantuml_config(diagram_text, diagram_type, doc, logger)
@@ -164,6 +165,7 @@ def process(processor, parent, attrs, diagram_type, diagram_text, logger)
         block.assign_caption(caption, 'figure')
         block
       end
+      # rubocop:enable Metrics/AbcSize
 
       private
 
@@ -174,7 +176,7 @@ def prepend_plantuml_config(diagram_text, diagram_type, doc, logger)
           plantuml_include_path = doc.normalize_system_path(doc.attr('kroki-plantuml-include'))
           if ::File.readable? plantuml_include_path
             config = File.read(plantuml_include_path)
-            diagram_text = config + "\n" + diagram_text
+            diagram_text = "#{config}\n#{diagram_text}"
           else
             logger.warn "Unable to read plantuml-include. File not found or not readable: #{plantuml_include_path}."
           end
@@ -258,9 +260,7 @@ class KrokiDiagram
     require 'zlib'
     require 'digest'
 
-    attr_reader :type
-    attr_reader :text
-    attr_reader :format
+    attr_reader :type, :text, :format
 
     def initialize(type, format, text)
       @text = text
@@ -280,11 +280,10 @@ def save(output_dir_path, kroki_client)
       diagram_url = get_diagram_uri(kroki_client.server_url)
       diagram_name = "diag-#{Digest::SHA256.hexdigest diagram_url}.#{@format}"
       file_path = File.join(output_dir_path, diagram_name)
-      encoding = if @format == 'txt' || @format == 'atxt' || @format == 'utxt'
+      encoding = case @format
+                 when 'txt', 'atxt', 'utxt'
                    'utf8'
-                 elsif @format == 'svg'
-                   'binary'
-                 else
+                 when 'svg', 'binary'
                    'binary'
                  end
       # file is either (already) on the file system or we should read it from Kroki
@@ -303,12 +302,12 @@ def save(output_dir_path, kroki_client)
     def _join_uri_segments(base, *uris)
       segments = []
       # remove trailing slashes
-      segments.push(base.gsub(%r{[/]+$}, ''))
+      segments.push(base.gsub(%r{/+$}, ''))
       segments.concat(uris.map do |uri|
         # remove leading and trailing slashes
         uri.to_s
-          .gsub(%r{^[/]+}, '')
-          .gsub(%r{[/]+$}, '')
+          .gsub(%r{^/+}, '')
+          .gsub(%r{/+$}, '')
       end)
       segments.join('/')
     end
@@ -317,9 +316,7 @@ def _join_uri_segments(base, *uris)
   # Kroki client
   #
   class KrokiClient
-    attr_reader :server_url
-    attr_reader :method
-    attr_reader :max_uri_length
+    attr_reader :server_url, :method, :max_uri_length
 
     SUPPORTED_HTTP_METHODS = %w[get post adaptive].freeze
 
diff --git a/ruby/spec/asciidoctor_kroki_block_macro_spec.rb b/ruby/spec/asciidoctor_kroki_block_macro_spec.rb
index 3825290a..b775d304 100644
--- a/ruby/spec/asciidoctor_kroki_block_macro_spec.rb
+++ b/ruby/spec/asciidoctor_kroki_block_macro_spec.rb
@@ -1,3 +1,4 @@
+# rubocop:disable Lint/ConstantDefinitionInBlock
 # frozen_string_literal: true
 
 require 'rspec_helper'
@@ -126,3 +127,4 @@ def unresolved_block_macro_message(name, target)
     end
   end
 end
+# rubocop:enable Lint/ConstantDefinitionInBlock
diff --git a/ruby/spec/asciidoctor_kroki_spec.rb b/ruby/spec/asciidoctor_kroki_spec.rb
index ff8f1e0d..ed4d2c22 100644
--- a/ruby/spec/asciidoctor_kroki_spec.rb
+++ b/ruby/spec/asciidoctor_kroki_spec.rb
@@ -134,7 +134,7 @@
     it 'should instantiate block processor without warning' do
       original_stderr = $stderr
       $stderr = StringIO.new
-      ::AsciidoctorExtensions::KrokiBlockProcessor.new 'plantuml'.to_sym, {}
+      ::AsciidoctorExtensions::KrokiBlockProcessor.new :plantuml, {}
       output = $stderr.string
       (expect output).to eql ''
     ensure