diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..931d082
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,37 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby: ["3.2", "3.3", "3.4", "4.0"]
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          bundler-cache: true
+
+      - run: bundle exec rspec
+
+  lint:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: "3.4"
+          bundler-cache: true
+
+      - run: bundle exec rubocop
diff --git a/.rubocop.yml b/.rubocop.yml
index 67ab06a..2416daa 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -1,4 +1,8 @@
-Documentation:
+AllCops:
+  TargetRubyVersion: 3.2
+  NewCops: enable
+
+Style/Documentation:
   Enabled: false
 
 Style/StringLiterals:
@@ -11,5 +15,12 @@ Metrics/BlockLength:
   Exclude:
     - spec/**/*
 
-Metrics/LineLength:
+Layout/LineLength:
   Max: 120
+
+Gemspec/DevelopmentDependencies:
+  EnforcedStyle: gemspec
+
+Metrics/ClassLength:
+  Exclude:
+    - lib/deepl_diff/tokenizer.rb
diff --git a/.ruby-version b/.ruby-version
new file mode 100644
index 0000000..7636e75
--- /dev/null
+++ b/.ruby-version
@@ -0,0 +1 @@
+4.0.5
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index 26802db..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,12 +0,0 @@
-language: ruby
-sudo: false
-rvm:
-  - 2.3.3
-cache: bundler
-
-addons:
-  code_climate:
-    repo_token: "49b1afe0298c521f3d73377db0d20d1d4b9749ad533126bf3ed105fe9612eb0e"
-    
-after_success:
-  - bundle exec codeclimate-test-reporter
diff --git a/deepl_diff.gemspec b/deepl_diff.gemspec
index 6ad476c..0164398 100644
--- a/deepl_diff.gemspec
+++ b/deepl_diff.gemspec
@@ -4,7 +4,7 @@ lib = File.expand_path("lib", __dir__)
 $LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
 require "deepl_diff/version"
 
-# rubocop:disable Metrics/BlockLength
+# rubocop:disable-next Metrics/BlockLength
 Gem::Specification.new do |spec|
   spec.name          = "deepl_diff"
   spec.version       = DeepLDiff::VERSION
@@ -21,12 +21,16 @@ DeepL API wrapper for Ruby which helps to translate only changes
 between revisions of long texts.
   )
   spec.homepage = "https://github.com/Halvanhelv/deepl_diff"
+  spec.required_ruby_version = ">= 3.2"
 
   if spec.respond_to?(:metadata)
     spec.metadata["allowed_push_host"] = "https://rubygems.org"
+    spec.metadata["homepage_uri"] = spec.homepage
+    spec.metadata["source_code_uri"] = spec.homepage
+    spec.metadata["rubygems_mfa_required"] = "true"
   else
     raise "RubyGems 2.0 or newer is required to protect against " \
-      "public gem pushes."
+          "public gem pushes."
   end
 
   spec.files = `git ls-files -z`.split("\x0").reject do |f|
@@ -36,20 +40,17 @@ between revisions of long texts.
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
   spec.require_paths = ["lib"]
 
-  spec.add_development_dependency "bundler", "~> 1.14"
-  spec.add_development_dependency "codeclimate-test-reporter", "~> 1.0.0"
-  spec.add_development_dependency "rake", "~> 10.0"
-  spec.add_development_dependency "rspec", "~> 3.0"
-  spec.add_development_dependency "rubocop"
-  spec.add_development_dependency "simplecov"
-
-  spec.add_dependency "connection_pool"
-  spec.add_dependency "deepl-rb"
-  spec.add_dependency "dry-initializer"
-  spec.add_dependency "ox"
-  spec.add_dependency "punkt-segmenter"
-  spec.add_dependency "ratelimit"
-  spec.add_dependency "redis"
-  spec.add_dependency "redis-namespace"
+  spec.add_development_dependency "rake", "~> 13.0"
+  spec.add_development_dependency "rspec", "~> 3.13"
+  spec.add_development_dependency "rubocop", "~> 1.90"
+  spec.add_development_dependency "simplecov", "~> 1.2"
+
+  spec.add_dependency "connection_pool", ">= 2.4", "< 4.0"
+  spec.add_dependency "deepl-rb", "~> 3.9"
+  spec.add_dependency "dry-initializer", "~> 3.2"
+  spec.add_dependency "ox", "~> 2.14"
+  spec.add_dependency "punkt-segmenter", "~> 0.9"
+  spec.add_dependency "ratelimit", "~> 1.1"
+  spec.add_dependency "redis", ">= 5.0", "< 7.0"
+  spec.add_dependency "redis-namespace", "~> 1.11"
 end
-# rubocop:enable Metrics/BlockLength
diff --git a/lib/deepl_diff.rb b/lib/deepl_diff.rb
index 47ec036..8c6d75e 100644
--- a/lib/deepl_diff.rb
+++ b/lib/deepl_diff.rb
@@ -1,5 +1,10 @@
 # frozen_string_literal: true
 
+require "cgi/escape"
+require "digest/md5"
+require "forwardable"
+require "stringio"
+
 require "ox"
 require "punkt-segmenter"
 require "dry/initializer"
@@ -19,8 +24,8 @@ module DeepLDiff
   class << self
     attr_accessor :api, :cache_store, :rate_limiter
 
-    def translate(*args)
-      Request.new(*args).call
+    def translate(*)
+      Request.new(*).call
     end
   end
 
diff --git a/lib/deepl_diff/chunker.rb b/lib/deepl_diff/chunker.rb
index 607e133..c9cc6e4 100644
--- a/lib/deepl_diff/chunker.rb
+++ b/lib/deepl_diff/chunker.rb
@@ -5,14 +5,17 @@ class DeepLDiff::Chunker
 
   class Error < StandardError; end
 
-  Chunk = Struct.new(:values, :size)
+  Chunk = Struct.new(:texts, :bytesize)
+
+  MAX_CHUNK_SIZE = 1700
+  COUNT_LIMIT = 300
 
   param :values
   option :limit, default: proc { MAX_CHUNK_SIZE }
   option :count_limit, default: proc { COUNT_LIMIT }
 
   def call
-    chunks.map(&:values)
+    chunks.map(&:texts)
   end
 
   def chunks
@@ -34,8 +37,8 @@ def chunks
 
   def next_chunk?(tail, value)
     tail.nil? ||
-      (size(value) + tail.size > limit) ||
-      tail.values.size > count_limit
+      (size(value) + tail.bytesize > limit) ||
+      tail.texts.size > count_limit
   end
 
   def size(text)
@@ -43,14 +46,11 @@ def size(text)
   end
 
   def update_chunk(chunk, value)
-    chunk.values << value
-    chunk.size = chunk.size + value.size
+    chunk.texts << value
+    chunk.bytesize += value.size
   end
 
   def validate_value_size(value)
     raise Error, "Too long part #{value.size} > #{limit}" if value.size > limit
   end
-
-  MAX_CHUNK_SIZE = 1700
-  COUNT_LIMIT = 300
 end
diff --git a/lib/deepl_diff/linearizer.rb b/lib/deepl_diff/linearizer.rb
index b0e8f61..1b9e189 100644
--- a/lib/deepl_diff/linearizer.rb
+++ b/lib/deepl_diff/linearizer.rb
@@ -5,7 +5,7 @@ class << self
     def linearize(struct, array = [])
       case struct
       when Hash
-        struct.each { |_k, v| linearize(v, array) }
+        struct.each_value { |v| linearize(v, array) }
       when Array
         struct.each { |v| linearize(v, array) }
       else
diff --git a/lib/deepl_diff/request.rb b/lib/deepl_diff/request.rb
index fff6fdd..87b461f 100644
--- a/lib/deepl_diff/request.rb
+++ b/lib/deepl_diff/request.rb
@@ -99,13 +99,13 @@ def chunks_translated
   # Restores indexes for translated tokens
   # => { ..., "1_1" => "Horoshiy", 1_3 => "Malchik", ... }
   def text_tokens_translated
-    @text_tokens_texts_translated ||=
+    @text_tokens_translated ||=
       restore(text_tokens, chunks_translated.flatten)
   end
 
   # Restores tokens translated + adds same spacing as in source token
   # => [[..., [ "Horoshiy", :text ], ...]]
-  # rubocop:disable Metrics/AbcSize
+  # rubocop:disable-next Metrics/AbcSize
   def tokens_translated
     @tokens_translated ||= tokens.dup.tap do |tokens|
       text_tokens_translated.each do |index, value|
@@ -115,7 +115,6 @@ def tokens_translated
       end
     end
   end
-  # rubocop:enable Metrics/AbcSize
 
   def restore_spacing(source_value, value)
     DeepLDiff::Spacing.restore(source_value, value)
@@ -136,7 +135,7 @@ def translation
 
   def call_api(values)
     check_rate_limit(values)
-    [api.translate(values, from, to, **options)].flatten.map(&:text)
+    [api.translate(values, from, to, options)].flatten.map(&:text)
   end
 
   def cache
diff --git a/lib/deepl_diff/tokenizer.rb b/lib/deepl_diff/tokenizer.rb
index 8c8c607..a609ec3 100644
--- a/lib/deepl_diff/tokenizer.rb
+++ b/lib/deepl_diff/tokenizer.rb
@@ -1,6 +1,12 @@
 # frozen_string_literal: true
 
-class DeepLDiff::Tokenizer < ::Ox::Sax
+class DeepLDiff::Tokenizer < Ox::Sax
+  SKIP = %i[script style].freeze
+  INNER_SPANS = %i[notranslate span end_span end_notranslate].freeze
+  HTML_OPTIONS = { smart: true, skip: :skip_none }.freeze
+
+  # Ox::Sax provides no initializer to chain to.
+  # rubocop:disable-next Lint/MissingSuper
   def initialize(source)
     @pos = nil
     @source = source
@@ -38,7 +44,7 @@ def text(value)
     return if value == ""
 
     @sequence << (SKIP.include?(@context.last) ? :markup : :text)
-    @indicies << @pos - 1
+    @indicies << (@pos - 1)
   end
 
   def tokens
@@ -69,7 +75,7 @@ def make_sentences_from_last_token(tokens)
     tokens.concat(sentences(tokens.pop[0])) if tokens.last[1] == :text
   end
 
-  # rubocop: disable Metrics/MethodLength
+  # rubocop: disable-next Metrics/MethodLength
   def sentences(value)
     return [] if value.strip.empty?
 
@@ -87,7 +93,6 @@ def sentences(value)
       [value[left..right], :text]
     end
   end
-  # rubocop:enable Metrics/MethodLength
 
   # Whether the sequence is between `:notranslate` and `:end_notranslate`
   def notranslate?
@@ -129,7 +134,7 @@ def start_markup(name)
                   else
                     :markup
                   end)
-    @indicies << @pos - 1
+    @indicies << (@pos - 1)
   end
 
   def end_markup(name)
@@ -139,7 +144,7 @@ def end_markup(name)
                   else
                     :markup
                   end)
-    @indicies << @pos - 1 unless @pos == @source.bytesize
+    @indicies << (@pos - 1) unless @pos == @source.bytesize
   end
 
   class << self
@@ -152,8 +157,4 @@ def tokenize(value)
       tokenizer.tokens
     end
   end
-
-  SKIP = %i[script style].freeze
-  INNER_SPANS = %i[notranslate span end_span end_notranslate].freeze
-  HTML_OPTIONS = { smart: true, skip: :skip_none }.freeze
 end
diff --git a/lib/deepl_diff/version.rb b/lib/deepl_diff/version.rb
index 976f8f8..8608e35 100644
--- a/lib/deepl_diff/version.rb
+++ b/lib/deepl_diff/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module DeepLDiff
-  VERSION = "1.0.2"
+  VERSION = "1.1.0"
 end
diff --git a/spec/deepl_diff/request_spec.rb b/spec/deepl_diff/request_spec.rb
index b156d2c..1b4cd55 100644
--- a/spec/deepl_diff/request_spec.rb
+++ b/spec/deepl_diff/request_spec.rb
@@ -5,9 +5,13 @@
 RSpec.describe DeepLDiff::Request do
   subject { described_class.new(values, options).call }
 
+  # OpenStruct is no longer available by default, and the API response only
+  # needs to expose #text.
+  translation = Struct.new(:text)
+
   let(:api) { double("API") }
   let(:cache_store) { double("Cache store") }
-  let(:api_response_wrap) { api_response.map { |v| OpenStruct.new(text: v) } }
+  let(:api_response_wrap) { api_response.map { |v| translation.new(v) } }
   let(:cache_response) { nil }
 
   before do
diff --git a/spec/deepl_diff/tokenizer_spec.rb b/spec/deepl_diff/tokenizer_spec.rb
index 4b058ca..769151d 100644
--- a/spec/deepl_diff/tokenizer_spec.rb
+++ b/spec/deepl_diff/tokenizer_spec.rb
@@ -134,8 +134,8 @@
   context "notranslate inside another notranslate" do
     let(:source) do
       "<span class='notranslate'>foo" \
-      "<span class='notranslate'>bar</span>baz" \
-      "</span>"
+        "<span class='notranslate'>bar</span>baz" \
+        "</span>"
     end
 
     let(:tokens) do
@@ -166,7 +166,7 @@
   context "with <?xml:...> tag" do
     let(:source) do
       "Hey!<br />Look!" \
-      "<?xml:namespace ns=\"urn:office\" ?>"
+        "<?xml:namespace ns=\"urn:office\" ?>"
     end
 
     let(:tokens) do
@@ -184,7 +184,7 @@
   context "bizarre sentences" do
     let(:source) do
       "Набор «Солнечная механика» от 4М — это 6 экспериментов." \
-      "\n\nЮному изобретателю предстоит воочию посмотреть на чудеса."
+        "\n\nЮному изобретателю предстоит воочию посмотреть на чудеса."
     end
 
     let(:tokens) do