diff --git a/.codeclimate.yml b/.codeclimate.yml
index 25fc0fd..63761a9 100644
--- a/.codeclimate.yml
+++ b/.codeclimate.yml
@@ -2,7 +2,3 @@ checks:
   method-complexity:
     config:
       threshold: 6 # should be just fine
-
-plugins:
-  rubocop:
-    enabled: true
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d9f39b0..f4084e0 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -3,15 +3,15 @@ name: Lint & Test
 on: [push, pull_request]
 
 jobs:
-  # lint:
-  #   runs-on: ubuntu-latest
-  #   steps:
-  #     - uses: actions/checkout@v3
-  #     - uses: ruby/setup-ruby@v1
-  #       with:
-  #         ruby-version: '3.0'
-  #         bundler-cache: true
-  #     - run: bundle exec rubocop
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: '3.2'
+          bundler-cache: true
+      - run: bundle exec rubocop
 
   test:
     runs-on: ubuntu-latest
diff --git a/.rubocop.yml b/.rubocop.yml
index 53ce884..4c21695 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -1,15 +1,18 @@
-# Rubocop does not support 2.0
-Gemspec/RequiredRubyVersion: {Enabled: false}
+require: rubocop-rails
 
-Rails: {Enabled: true}
+AllCops:
+  TargetRubyVersion: 2.4
+  NewCops: enable
+  SuggestExtensions: false
+  Exclude:
+    - gemfiles/*
+    - tmp/*
+    - vendor/**/* # for github actions
 
-Layout/AlignParameters:
-  # Disable, till rubocop supports combination of styles.
-  # Use one of this styles where appropriate, keep it clean, compact and readable.
-  Enabled: false
-  # EnforcedStyle:
-  # - with_first_parameter
-  # - with_fixed_indentation
+Gemspec/DevelopmentDependencies: {Enabled: false}
+
+Layout/ArgumentAlignment: {EnforcedStyle: with_fixed_indentation}
+Layout/ParameterAlignment: {EnforcedStyle: with_fixed_indentation}
 
 # Breaks
 #
@@ -19,7 +22,11 @@ Layout/AlignParameters:
 #   )
 Layout/ClosingParenthesisIndentation: {Enabled: false}
 Layout/DotPosition: {EnforcedStyle: trailing}
+Layout/EmptyLineAfterGuardClause: {Enabled: false}
 Layout/FirstParameterIndentation: {EnforcedStyle: consistent}
+Layout/LineContinuationLeadingSpace: {Enabled: false}
+Layout/LineEndStringConcatenationIndentation: {EnforcedStyle: indented}
+Layout/LineLength: {Max: 100}
 # Same as Layout/ClosingParenthesisIndentation
 Layout/MultilineMethodCallBraceLayout: {Enabled: false}
 Layout/MultilineMethodCallIndentation: {EnforcedStyle: indented}
@@ -28,8 +35,16 @@ Layout/SpaceInsideHashLiteralBraces: {EnforcedStyle: no_space}
 
 # Offences named scopes and `expect {}.to change {}`.
 Lint/AmbiguousBlockAssociation: {Enabled: false}
+Lint/EmptyBlock:
+  Exclude:
+    - spec/**/*
 
+Naming/FileName:
+  Exclude:
+    - lib/tasks/telegram-bot.rake
+Naming/MethodParameterName: {MinNameLength: 2}
 Naming/PredicateName: {Enabled: false}
+Naming/RescuedExceptionsVariableName: {PreferredName: exception}
 Naming/VariableNumber: {EnforcedStyle: snake_case}
 
 Style/Alias: {Enabled: false}
@@ -45,12 +60,16 @@ Style/ModuleFunction: {Enabled: false}
 Style/NestedParenthesizedCalls: {Enabled: false}
 Style/SignalException: {EnforcedStyle: only_raise}
 Style/TrailingCommaInArguments: {Enabled: false}
-Style/TrailingCommaInLiteral: {EnforcedStyleForMultiline: comma}
+Style/TrailingCommaInArrayLiteral: {EnforcedStyleForMultiline: comma}
+Style/TrailingCommaInHashLiteral: {EnforcedStyleForMultiline: comma}
 
 Metrics/AbcSize: {Max: 21}
 # Other metrics are just enough.
 # This one offences all specs, routes and some initializers.
 Metrics/BlockLength: {Enabled: false}
-Metrics/LineLength: {Max: 100}
 Metrics/MethodLength: {Max: 30}
 Metrics/CyclomaticComplexity: {Max: 8}
+
+Rails/IndexWith: {Enabled: false}
+Rails/RakeEnvironment: {Enabled: false}
+Rails/ShortI18n: {Enabled: false}
diff --git a/Appraisals b/Appraisals
index 019d01b..5ce8c11 100644
--- a/Appraisals
+++ b/Appraisals
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 appraise 'rails-71' do
   gem 'actionpack', '~> 7.1.0'
   gem 'railties', '~> 7.1.0'
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 48958dc..8a33d86 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,7 @@
 # Unreleased
 
+- Add `# frozen_string_literal: true` to all source files.
+
 # 0.16.1
 
 - Fix logger in poller mode in rails 7.1
diff --git a/Gemfile b/Gemfile
index 7499052..b83e6bd 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 source 'https://rubygems.org'
 gemspec
 
@@ -14,7 +16,8 @@ group :development do
   gem 'rspec-its', '~> 1.3.0'
   gem 'rspec-rails', '~> 4.0.2'
 
-  gem 'rubocop', '~> 0.52.1'
+  gem 'rubocop', '~> 1.59.0'
+  gem 'rubocop-rails', '~> 2.23.1'
 
   gem 'coveralls', '~> 0.8.23', require: false
 end
diff --git a/Rakefile b/Rakefile
index a000ffb..de9f76c 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'bundler/gem_tasks'
 require 'rspec/core/rake_task'
 
diff --git a/bin/console b/bin/console
index 604f587..7d15701 100755
--- a/bin/console
+++ b/bin/console
@@ -1,4 +1,5 @@
 #!/usr/bin/env ruby
+# frozen_string_literal: true
 
 require 'bundler/setup'
 require 'telegram/bot'
diff --git a/bin/fetch-telegram-methods b/bin/fetch-telegram-methods
index 193d19a..097b94f 100755
--- a/bin/fetch-telegram-methods
+++ b/bin/fetch-telegram-methods
@@ -1,4 +1,6 @@
 #!/usr/bin/env ruby
+# frozen_string_literal: true
+
 #
 # Fetch list of methods from Telegram docs.
 # Use it to update client.rb.
@@ -6,7 +8,7 @@
 require 'net/http'
 require 'nokogiri'
 
-DOCS_URL = 'https://core.telegram.org/bots/api'.freeze
+DOCS_URL = 'https://core.telegram.org/bots/api'
 
 page_html = Net::HTTP.get(URI(DOCS_URL))
 doc = Nokogiri::HTML(page_html)
@@ -18,11 +20,11 @@ headers = doc.css('h3, h4').
   map { |g| g.map(&:text) }
 
 # Method starts with lowercase and does not have spaces.
-NOT_METHOD_REGEXP = /(\A[^a-z])|\s/
+NOT_METHOD_REGEXP = /(\A[^a-z])|\s/.freeze
 
 # Filter method names.
 method_list = headers.
-  map { |g| g.reject { |x| x.match?(NOT_METHOD_REGEXP) } }.
+  map { |g| g.grep_v(NOT_METHOD_REGEXP) }.
   reject(&:empty?)
 
 api_version = doc.text.match(/^(?:Introducing )?(Bot API ([\d\.]+))\.?$/)
diff --git a/bin/install_git_hooks b/bin/install_git_hooks
index 4b48122..67eca3b 100755
--- a/bin/install_git_hooks
+++ b/bin/install_git_hooks
@@ -1,6 +1,7 @@
 #!/usr/bin/env ruby
+# frozen_string_literal: true
 
-root = File.expand_path('../../', __FILE__)
+root = File.expand_path('..', __dir__)
 hooks_dir = "#{root}/bin/git-hooks"
 
 `ls -1 #{hooks_dir}`.each_line.map(&:strip).each do |file|
diff --git a/lib/tasks/telegram-bot.rake b/lib/tasks/telegram-bot.rake
index c62ed89..04422d6 100644
--- a/lib/tasks/telegram-bot.rake
+++ b/lib/tasks/telegram-bot.rake
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 namespace :telegram do
   namespace :bot do
     desc 'Run poller. It broadcasts Rails.logger to STDOUT in dev like `rails s` do. ' \
@@ -6,14 +8,14 @@ namespace :telegram do
       ENV['BOT_POLLER_MODE'] = 'true'
       Rake::Task['environment'].invoke
       if ENV.fetch('LOG_TO_STDOUT') { Rails.env.development? }.present?
-        console = ActiveSupport::Logger.new(STDERR)
-        if ::Rails.logger.respond_to?(:broadcast_to)
-          ::Rails.logger.broadcast_to(console)
+        console = ActiveSupport::Logger.new($stderr)
+        if Rails.logger.respond_to?(:broadcast_to)
+          Rails.logger.broadcast_to(console)
         else
           Rails.logger.extend ActiveSupport::Logger.broadcast console
         end
       end
-      Telegram::Bot::UpdatesPoller.start(ENV['BOT'].try!(:to_sym) || :default)
+      Telegram::Bot::UpdatesPoller.start(ENV['BOT']&.to_sym || :default)
     end
 
     desc 'Set webhook urls for all bots'
diff --git a/lib/telegram/bot.rb b/lib/telegram/bot.rb
index 799cefe..393419f 100644
--- a/lib/telegram/bot.rb
+++ b/lib/telegram/bot.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'telegram/bot/config_methods'
 
 module Telegram
@@ -12,15 +14,6 @@ module Telegram
     # Raised for valid telegram response with 404 status code.
     class NotFound < Error; end
 
-    module_function
-
-    def deprecation_0_16
-      @deprecation ||= begin
-        require 'active_support/deprecation'
-        ActiveSupport::Deprecation.new('0.16', 'Telegram::Bot')
-      end
-    end
-
     autoload :Async,              'telegram/bot/async'
     autoload :Client,             'telegram/bot/client'
     autoload :ClientStub,         'telegram/bot/client_stub'
@@ -30,6 +23,7 @@ module Telegram
     autoload :Tasks,              'telegram/bot/tasks'
     autoload :UpdatesController,  'telegram/bot/updates_controller'
     autoload :UpdatesPoller,      'telegram/bot/updates_poller'
+    autoload :VERSION,            'telegram/bot/version'
   end
 end
 
diff --git a/lib/telegram/bot/async.rb b/lib/telegram/bot/async.rb
index 268bf22..47de98d 100644
--- a/lib/telegram/bot/async.rb
+++ b/lib/telegram/bot/async.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Telegram
   module Bot
     # Telegram clients can perform requests in async way with
@@ -128,7 +130,7 @@ module Telegram
       #
       # If no block is given returns previously set value or the global one,
       # set by #async=.
-      def async(val = true)
+      def async(val = true) # rubocop:disable Style/OptionalBooleanParameter
         thread_key = object_id
         thread_store = Async.thread_store
         return thread_store.fetch(thread_key) { @async } unless block_given?
@@ -137,7 +139,7 @@ module Telegram
           thread_store[thread_key] = self.class.prepare_async_val(val)
           yield
         ensure
-          if MISSING_VALUE == old_val
+          if old_val == MISSING_VALUE
             thread_store.delete(thread_key)
           else
             thread_store[thread_key] = old_val
diff --git a/lib/telegram/bot/client.rb b/lib/telegram/bot/client.rb
index 79e018f..153975f 100644
--- a/lib/telegram/bot/client.rb
+++ b/lib/telegram/bot/client.rb
@@ -1,11 +1,13 @@
+# frozen_string_literal: true
+
 require 'active_support/core_ext/hash/keys'
 require 'httpclient'
 
 module Telegram
   module Bot
     class Client
-      SERVER = 'https://api.telegram.org'.freeze
-      URL_TEMPLATE = '%<server>s/bot%<token>s/'.freeze
+      SERVER = 'https://api.telegram.org'
+      URL_TEMPLATE = '%<server>s/bot%<token>s/'
 
       autoload :RequestBodyFormatter, 'telegram/bot/client/request_body_formatter'
       autoload :TypedResponse, 'telegram/bot/client/typed_response'
@@ -41,7 +43,7 @@ module Telegram
         end
 
         def error_for_response(response)
-          result = JSON.parse(response.body) rescue nil # rubocop:disable RescueModifier
+          result = JSON.parse(response.body) rescue nil # rubocop:disable Style/RescueModifier
           return Error.new(response.reason) unless result
           message = result['description'] || '-'
           # This errors are raised only for valid responses from Telegram
diff --git a/lib/telegram/bot/client/api_helper.rb b/lib/telegram/bot/client/api_helper.rb
index ee33d8b..e4a7cda 100644
--- a/lib/telegram/bot/client/api_helper.rb
+++ b/lib/telegram/bot/client/api_helper.rb
@@ -1,10 +1,12 @@
+# frozen_string_literal: true
+
 require 'active_support/core_ext/string/inflections'
 
 module Telegram
   module Bot
     class Client
       module ApiHelper
-        METHODS_LIST_FILE = File.expand_path('../api_methods.txt', __FILE__)
+        METHODS_LIST_FILE = File.expand_path('api_methods.txt', __dir__)
 
         class << self
           def methods_list(file = METHODS_LIST_FILE)
diff --git a/lib/telegram/bot/client/request_body_formatter.rb b/lib/telegram/bot/client/request_body_formatter.rb
index 385e1a1..bcae116 100644
--- a/lib/telegram/bot/client/request_body_formatter.rb
+++ b/lib/telegram/bot/client/request_body_formatter.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'json'
 
 module Telegram
diff --git a/lib/telegram/bot/client/typed_response.rb b/lib/telegram/bot/client/typed_response.rb
index b8ae24d..ad74319 100644
--- a/lib/telegram/bot/client/typed_response.rb
+++ b/lib/telegram/bot/client/typed_response.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'telegram/bot/client/api_helper'
 require 'active_support/core_ext/string/inflections'
 
diff --git a/lib/telegram/bot/client_stub.rb b/lib/telegram/bot/client_stub.rb
index 2491bb8..3e2cc6e 100644
--- a/lib/telegram/bot/client_stub.rb
+++ b/lib/telegram/bot/client_stub.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Telegram
   module Bot
     # Stubbed client for tests. Saves all requests into #requests hash.
@@ -17,7 +19,7 @@ module Telegram
       class << self
         # Any call to Client.new will return ClientStub instance when `enabled` is true.
         # Can be used with a block.
-        def stub_all!(enabled = true)
+        def stub_all!(enabled = true) # rubocop:disable Style/OptionalBooleanParameter
           Client.extend(StubbedConstructor) unless Client < StubbedConstructor
           return @_stub_all = enabled unless block_given?
           begin
@@ -34,7 +36,7 @@ module Telegram
         end
       end
 
-      def initialize(token = nil, username = nil, **options)
+      def initialize(token = nil, username = nil, **options) # rubocop:disable Lint/MissingSuper
         @token = token || options[:token]
         @username = username || options[:username] || token
         reset
diff --git a/lib/telegram/bot/config_methods.rb b/lib/telegram/bot/config_methods.rb
index 154371c..63a9c1f 100644
--- a/lib/telegram/bot/config_methods.rb
+++ b/lib/telegram/bot/config_methods.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'active_support/core_ext/hash/keys'
 require 'active_support/core_ext/hash/indifferent_access'
 
@@ -44,7 +46,7 @@ module Telegram
       # from `secrets.yml` merging `telegram['bot']` at `:default` key.
       #
       # Can be overwritten with .bots_config=
-      def bots_config
+      def bots_config # rubocop:disable Metrics/PerceivedComplexity
         @bots_config ||=
           if defined?(Rails.application)
             app = Rails.application
diff --git a/lib/telegram/bot/debug_client.rb b/lib/telegram/bot/debug_client.rb
index 4a8a733..244b7ff 100644
--- a/lib/telegram/bot/debug_client.rb
+++ b/lib/telegram/bot/debug_client.rb
@@ -1,7 +1,9 @@
+# frozen_string_literal: true
+
 module Telegram
   module Bot
     module DebugClient
-      def debug!(dev = STDOUT)
+      def debug!(dev = $stdout)
         if block_given?
           begin
             old_dev = client.debug_dev
diff --git a/lib/telegram/bot/middleware.rb b/lib/telegram/bot/middleware.rb
index fa86d74..411bc7b 100644
--- a/lib/telegram/bot/middleware.rb
+++ b/lib/telegram/bot/middleware.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'active_support/concern'
 require 'active_support/core_ext/hash/indifferent_access'
 require 'active_support/json'
@@ -21,7 +23,7 @@ module Telegram
       end
 
       def inspect
-        "#<#{self.class.name}(#{controller.try!(:name)})>"
+        "#<#{self.class.name}(#{controller&.name})>"
       end
     end
   end
diff --git a/lib/telegram/bot/railtie.rb b/lib/telegram/bot/railtie.rb
index cc6fee4..54fffd7 100644
--- a/lib/telegram/bot/railtie.rb
+++ b/lib/telegram/bot/railtie.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'telegram/bot/routes_helper'
 
 module Telegram
@@ -10,7 +12,7 @@ module Telegram
       end
 
       config.before_initialize do
-        ::ActionDispatch::Routing::Mapper.send(:include, RoutesHelper)
+        ::ActionDispatch::Routing::Mapper.include RoutesHelper
       end
 
       initializer 'telegram.bot.updates_controller.set_config' do |app|
diff --git a/lib/telegram/bot/routes_helper.rb b/lib/telegram/bot/routes_helper.rb
index 8aca8af..bdace0b 100644
--- a/lib/telegram/bot/routes_helper.rb
+++ b/lib/telegram/bot/routes_helper.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'base64'
 require 'openssl'
 
diff --git a/lib/telegram/bot/rspec.rb b/lib/telegram/bot/rspec.rb
index aeba788..2186126 100644
--- a/lib/telegram/bot/rspec.rb
+++ b/lib/telegram/bot/rspec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Telegram
   module Bot
     module RSpec
diff --git a/lib/telegram/bot/rspec/callback_query_helpers.rb b/lib/telegram/bot/rspec/callback_query_helpers.rb
index 64a22fe..51d201d 100644
--- a/lib/telegram/bot/rspec/callback_query_helpers.rb
+++ b/lib/telegram/bot/rspec/callback_query_helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'telegram/bot/rspec'
 require 'telegram/bot/rspec/message_helpers'
 
diff --git a/lib/telegram/bot/rspec/client_matchers.rb b/lib/telegram/bot/rspec/client_matchers.rb
index 3f805f9..76d4ca1 100644
--- a/lib/telegram/bot/rspec/client_matchers.rb
+++ b/lib/telegram/bot/rspec/client_matchers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Telegram
   module Bot
     module RSpec
@@ -61,14 +63,14 @@ module Telegram
 
           attr_reader :performed_requests, :description
 
-          def initialize(bot, action, description: nil)
+          def initialize(bot, action, description: nil) # rubocop:disable Lint/MissingSuper
             @bot = bot
             @action = action
             @description = description || "make #{action} telegram request"
             exactly(1)
           end
 
-          def matches?(proc) # rubocop:disable AbcSize
+          def matches?(proc) # rubocop:disable Metrics/AbcSize
             raise ArgumentError, 'matcher only supports block expectations' unless proc.is_a?(Proc)
             original_requests_count = bot.requests[action].count
             proc.call
diff --git a/lib/telegram/bot/rspec/integration/poller.rb b/lib/telegram/bot/rspec/integration/poller.rb
index 54f7b8d..63c6526 100644
--- a/lib/telegram/bot/rspec/integration/poller.rb
+++ b/lib/telegram/bot/rspec/integration/poller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'telegram/bot/rspec/integration/shared'
 
 RSpec.shared_context 'telegram/bot/integration/poller' do
diff --git a/lib/telegram/bot/rspec/integration/rack.rb b/lib/telegram/bot/rspec/integration/rack.rb
index 520d90c..55ea13f 100644
--- a/lib/telegram/bot/rspec/integration/rack.rb
+++ b/lib/telegram/bot/rspec/integration/rack.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'telegram/bot/rspec/integration/shared'
 require 'rack/test'
 
diff --git a/lib/telegram/bot/rspec/integration/rails.rb b/lib/telegram/bot/rspec/integration/rails.rb
index 1e43e09..ad3aa7c 100644
--- a/lib/telegram/bot/rspec/integration/rails.rb
+++ b/lib/telegram/bot/rspec/integration/rails.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'telegram/bot/rspec/integration/shared'
 
 RSpec.shared_context 'telegram/bot/integration/rails', type: :request do
diff --git a/lib/telegram/bot/rspec/integration/shared.rb b/lib/telegram/bot/rspec/integration/shared.rb
index 73f3087..a6dab6f 100644
--- a/lib/telegram/bot/rspec/integration/shared.rb
+++ b/lib/telegram/bot/rspec/integration/shared.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'active_support/json'
 require 'telegram/bot'
 require 'telegram/bot/rspec/message_helpers'
@@ -10,5 +12,5 @@ RSpec.shared_context 'telegram/bot/integration/shared' do
 
   let(:bot) { Telegram.bot }
   let(:clear_session?) { described_class.respond_to?(:session_store) }
-  before { described_class.session_store.try!(:clear) if clear_session? }
+  before { described_class.session_store&.clear if clear_session? }
 end
diff --git a/lib/telegram/bot/rspec/message_helpers.rb b/lib/telegram/bot/rspec/message_helpers.rb
index 6585f0c..f3c222f 100644
--- a/lib/telegram/bot/rspec/message_helpers.rb
+++ b/lib/telegram/bot/rspec/message_helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Shared helpers for testing message updates.
 RSpec.shared_context 'telegram/bot/message_helpers' do
   let(:default_message_options) { {from: from, chat: chat} }
diff --git a/lib/telegram/bot/tasks.rb b/lib/telegram/bot/tasks.rb
index 2bd1787..a762757 100644
--- a/lib/telegram/bot/tasks.rb
+++ b/lib/telegram/bot/tasks.rb
@@ -7,7 +7,7 @@ module Telegram
 
       def set_webhook
         routes = Rails.application.routes.url_helpers
-        cert_file = ENV['CERT']
+        cert_file = ENV.fetch('CERT', nil)
         cert = File.open(cert_file) if cert_file
         each_bot do |key, bot|
           route_name = RoutesHelper.route_name_for_bot(bot)
@@ -16,7 +16,7 @@ module Telegram
           bot.set_webhook(
             url: url,
             certificate: cert,
-            ip_address: ENV['IP_ADDRESS'],
+            ip_address: ENV.fetch('IP_ADDRESS', nil),
             drop_pending_updates: drop_pending_updates,
           )
         end
@@ -50,13 +50,13 @@ module Telegram
       end
 
       def each_bot(&block)
-        id = ENV['BOT'].try!(:to_sym)
+        id = ENV['BOT']&.to_sym
         bots = id ? {id => Client.by_id(id)} : Telegram.bots
         bots.each { |key, bot| bot.async(false) { block[key, bot] } }
       end
 
       def drop_pending_updates
-        ENV['DROP_PENDING_UPDATES'].try!(:downcase) == 'true'
+        ENV['DROP_PENDING_UPDATES']&.downcase == 'true'
       end
     end
   end
diff --git a/lib/telegram/bot/updates_controller.rb b/lib/telegram/bot/updates_controller.rb
index ced8ed7..5520bc8 100644
--- a/lib/telegram/bot/updates_controller.rb
+++ b/lib/telegram/bot/updates_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'abstract_controller'
 require 'active_support/core_ext/string/inflections'
 require 'active_support/callbacks'
@@ -47,7 +49,7 @@ module Telegram
     #     ControllerClass.new(bot, from: telegram_user, chat: telegram_chat).
     #       process(:help, *args)
     #
-    class UpdatesController < AbstractController::Base # rubocop:disable ClassLength
+    class UpdatesController < AbstractController::Base # rubocop:disable Metrics/ClassLength
       abstract!
 
       %w[
@@ -69,12 +71,12 @@ module Telegram
       include AbstractController::Callbacks
       # Redefine callbacks with default terminator.
       if ActiveSupport::VERSION::MAJOR >= 5
-        define_callbacks  :process_action,
-                          skip_after_callbacks_if_terminated: true
+        define_callbacks :process_action,
+          skip_after_callbacks_if_terminated: true
       else
-        define_callbacks  :process_action,
-                          terminator: ->(_, result) { result == false },
-                          skip_after_callbacks_if_terminated: true
+        define_callbacks :process_action,
+          terminator: ->(_, result) { result == false },
+          skip_after_callbacks_if_terminated: true
       end
 
       include Commands
@@ -126,14 +128,14 @@ module Telegram
       # that update is nil.
       # ActionDispatch::Request object is passed in `webhook_request` when bot running
       # in webhook mode.
-      def initialize(bot = nil, update = nil, webhook_request = nil)
+      def initialize(bot = nil, update = nil, webhook_request = nil) # rubocop:disable Lint/MissingSuper
         if update.is_a?(Hash) && (update.key?(:from) || update.key?(:chat))
           options = update
           update = nil
         end
         @_bot = bot
         @_update = update
-        @_chat, @_from = options && options.values_at(:chat, :from)
+        @_chat, @_from = options&.values_at(:chat, :from)
         @_payload, @_payload_type = self.class.payload_from_update(update)
         @_webhook_request = webhook_request
       end
@@ -142,13 +144,13 @@ module Telegram
       # when there is no such field in payload.
       #
       # Can be overriden with `chat` option for #initialize.
-      def chat
-        @_chat ||=
+      def chat # rubocop:disable Metrics/PerceivedComplexity
+        @_chat ||= # rubocop:disable Naming/MemoizedInstanceVariableName
           if payload
             if payload.is_a?(Hash)
-              payload['chat'] || payload['message'] && payload['message']['chat']
+              payload['chat'] || (payload['message'] && payload['message']['chat'])
             else
-              payload.try(:chat) || payload.try(:message).try!(:chat)
+              payload.try(:chat) || payload.try(:message)&.chat
             end
           end
       end
@@ -156,7 +158,8 @@ module Telegram
       # Accessor to `'from'` field of payload. Can be overriden with `from` option
       # for #initialize.
       def from
-        @_from ||= payload.is_a?(Hash) ? payload['from'] : payload.try(:from)
+        @_from ||= # rubocop:disable Naming/MemoizedInstanceVariableName
+          payload.is_a?(Hash) ? payload['from'] : payload.try(:from)
       end
 
       # Processes current update.
@@ -221,7 +224,7 @@ module Telegram
       # Silently ignore unsupported messages to not fail when user crafts
       # an update with usupported command, callback query context, etc.
       def action_missing(action, *_args)
-        logger.debug { "The action '#{action}' is not defined in #{self.class.name}" } if logger
+        logger&.debug { "The action '#{action}' is not defined in #{self.class.name}" }
         nil
       end
 
diff --git a/lib/telegram/bot/updates_controller/callback_query_context.rb b/lib/telegram/bot/updates_controller/callback_query_context.rb
index 1dddff1..13dc3c5 100644
--- a/lib/telegram/bot/updates_controller/callback_query_context.rb
+++ b/lib/telegram/bot/updates_controller/callback_query_context.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Telegram
   module Bot
     class UpdatesController
diff --git a/lib/telegram/bot/updates_controller/commands.rb b/lib/telegram/bot/updates_controller/commands.rb
index 7e26abf..88ae1fd 100644
--- a/lib/telegram/bot/updates_controller/commands.rb
+++ b/lib/telegram/bot/updates_controller/commands.rb
@@ -1,9 +1,11 @@
+# frozen_string_literal: true
+
 module Telegram
   module Bot
     class UpdatesController
       #  Support for parsing commands
       module Commands
-        CMD_REGEX = %r{\A/([a-z\d_]{,31})(@(\S+))?(\s|$)}i
+        CMD_REGEX = %r{\A/([a-z\d_]{,31})(@(\S+))?(\s|$)}i.freeze
 
         class << self
           # Fetches command from text message. All subsequent words are returned
@@ -34,7 +36,7 @@ module Telegram
         def action_for_message
           cmd, args = Commands.command_from_text(payload['text'], bot_username)
           return unless cmd
-          [[action_for_command(cmd), type: :command, command: cmd], args]
+          [[action_for_command(cmd), {type: :command, command: cmd}], args]
         end
 
         alias_method :action_for_channel_post, :action_for_message
diff --git a/lib/telegram/bot/updates_controller/instrumentation.rb b/lib/telegram/bot/updates_controller/instrumentation.rb
index 112a438..a73aeaf 100644
--- a/lib/telegram/bot/updates_controller/instrumentation.rb
+++ b/lib/telegram/bot/updates_controller/instrumentation.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Telegram
   module Bot
     class UpdatesController
@@ -23,8 +25,8 @@ module Telegram
         def process_action(*args)
           raw_payload = {
             controller: self.class.name,
-            action:     action_name,
-            update:     update,
+            action: action_name,
+            update: update,
           }
           Instrumentation.instrument(:start_processing, raw_payload.dup)
           Instrumentation.instrument(:process_action, raw_payload) do |payload|
@@ -61,14 +63,14 @@ module Telegram
         #   end
         #
         # :api: plugin
-        def cleanup_view_runtime #:nodoc:
+        def cleanup_view_runtime # :nodoc:
           yield
         end
 
         # Every time after an action is processed, this method is invoked
         # with the payload, so you can add more information.
         # :api: plugin
-        def append_info_to_payload(_payload) #:nodoc:
+        def append_info_to_payload(_payload) # :nodoc:
         end
 
         module ClassMethods
@@ -76,7 +78,7 @@ module Telegram
           # controller process action. This method should return an array
           # with the messages to be added.
           # :api: plugin
-          def log_process_action(_payload) #:nodoc:
+          def log_process_action(_payload) # :nodoc:
             []
           end
         end
diff --git a/lib/telegram/bot/updates_controller/log_subscriber.rb b/lib/telegram/bot/updates_controller/log_subscriber.rb
index 60fe07f..5c6493b 100644
--- a/lib/telegram/bot/updates_controller/log_subscriber.rb
+++ b/lib/telegram/bot/updates_controller/log_subscriber.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'active_support/log_subscriber'
 
 module Telegram
@@ -8,7 +10,7 @@ module Telegram
           info do
             payload = event.payload
             "Processing by #{payload[:controller]}##{payload[:action]}\n" \
-            "  Update: #{payload[:update].to_json}"
+              "  Update: #{payload[:update].to_json}"
           end
         end
 
diff --git a/lib/telegram/bot/updates_controller/message_context.rb b/lib/telegram/bot/updates_controller/message_context.rb
index 34d5e31..72ccb35 100644
--- a/lib/telegram/bot/updates_controller/message_context.rb
+++ b/lib/telegram/bot/updates_controller/message_context.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Telegram
   module Bot
     class UpdatesController
@@ -48,12 +50,12 @@ module Telegram
         # it has higher priority than contextual action.
         def action_for_message
           val = message_context_session.delete(:context)
-          context = val && val.to_s
-          super || context && begin
-            args = payload['text'].try!(:split) || []
+          context = val&.to_s
+          super || (context && begin
+            args = payload['text']&.split || []
             action = action_for_message_context(context)
-            [[action, type: :message_context, context: context], args]
-          end
+            [[action, {type: :message_context, context: context}], args]
+          end)
         end
 
         # Save context for the next request.
diff --git a/lib/telegram/bot/updates_controller/reply_helpers.rb b/lib/telegram/bot/updates_controller/reply_helpers.rb
index 02a9371..fac4a46 100644
--- a/lib/telegram/bot/updates_controller/reply_helpers.rb
+++ b/lib/telegram/bot/updates_controller/reply_helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Telegram
   module Bot
     class UpdatesController
@@ -59,9 +61,9 @@ module Telegram
         # Edit message from callback query.
         def edit_message(type, params = {})
           params =
-            if message_id = payload['inline_message_id'] # rubocop:disable AssignmentInCondition
+            if message_id = payload['inline_message_id'] # rubocop:disable Lint/AssignmentInCondition
               params.merge(inline_message_id: message_id)
-            elsif message = payload['message'] # rubocop:disable AssignmentInCondition
+            elsif message = payload['message'] # rubocop:disable Lint/AssignmentInCondition
               params.merge(chat_id: message['chat']['id'], message_id: message['message_id'])
             else
               raise 'Can not edit message without `inline_message_id` or `message`'
diff --git a/lib/telegram/bot/updates_controller/rescue.rb b/lib/telegram/bot/updates_controller/rescue.rb
index 3a13f8a..37b58b5 100644
--- a/lib/telegram/bot/updates_controller/rescue.rb
+++ b/lib/telegram/bot/updates_controller/rescue.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'active_support/rescuable'
 
 module Telegram
@@ -11,7 +13,7 @@ module Telegram
 
         def process_action(*)
           super
-        rescue Exception => exception # rubocop:disable RescueException
+        rescue Exception => exception # rubocop:disable Lint/RescueException
           rescue_with_handler(exception) || raise
         end
       end
diff --git a/lib/telegram/bot/updates_controller/rspec_helpers.rb b/lib/telegram/bot/updates_controller/rspec_helpers.rb
index 16f908d..2f2149a 100644
--- a/lib/telegram/bot/updates_controller/rspec_helpers.rb
+++ b/lib/telegram/bot/updates_controller/rspec_helpers.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'telegram/bot/updates_controller/testing'
 require 'telegram/bot/rspec/message_helpers'
 require 'telegram/bot/rspec/callback_query_helpers'
diff --git a/lib/telegram/bot/updates_controller/session.rb b/lib/telegram/bot/updates_controller/session.rb
index c40313e..cd2dae5 100644
--- a/lib/telegram/bot/updates_controller/session.rb
+++ b/lib/telegram/bot/updates_controller/session.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'rack/session/abstract/id'
 require 'active_support/cache'
 
@@ -27,7 +29,8 @@ module Telegram
         protected
 
         def session
-          @_session ||= self.class.build_session(session_key)
+          @_session ||= # rubocop:disable Naming/MemoizedInstanceVariableName
+            self.class.build_session(session_key)
         end
 
         def session_key
@@ -41,7 +44,7 @@ module Telegram
         class SessionHash < Rack::Session::Abstract::SessionHash
           attr_reader :id
 
-          def initialize(store, id)
+          def initialize(store, id) # rubocop:disable Lint/MissingSuper
             @store = store
             @id = id
           end
@@ -65,13 +68,13 @@ module Telegram
 
           def commit
             return unless loaded?
-            data = to_hash.delete_if { |_, v| v.nil? }
+            data = to_hash.compact
             @store.write(id, data)
           end
         end
 
         class NullSessionHash < Session::SessionHash
-          def initialize
+          def initialize # rubocop:disable Lint/MissingSuper
             @data = {}
             @loaded = true
             @exists = true
diff --git a/lib/telegram/bot/updates_controller/testing.rb b/lib/telegram/bot/updates_controller/testing.rb
index e1c700b..57c8865 100644
--- a/lib/telegram/bot/updates_controller/testing.rb
+++ b/lib/telegram/bot/updates_controller/testing.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Telegram
   module Bot
     class UpdatesController
@@ -16,7 +18,7 @@ module Telegram
         # everything will be rewriten with #initialize.
         #
         # With `full` set to `true` it'll clear all cached instance variables.
-        def recycle!(full = false)
+        def recycle!(full = false) # rubocop:disable Style/OptionalBooleanParameter
           return unless full
           (instance_variables - IVARS_TO_KEEP).each do |ivar|
             remove_instance_variable(ivar)
@@ -27,7 +29,8 @@ module Telegram
 
         # Stubs session.
         def session
-          @_session ||= Session::NullSessionHash.new
+          @_session ||= # rubocop:disable Naming/MemoizedInstanceVariableName
+            Session::NullSessionHash.new
         end
       end
     end
diff --git a/lib/telegram/bot/updates_controller/translation.rb b/lib/telegram/bot/updates_controller/translation.rb
index 179f76a..2b4fa84 100644
--- a/lib/telegram/bot/updates_controller/translation.rb
+++ b/lib/telegram/bot/updates_controller/translation.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Telegram
   module Bot
     class UpdatesController
diff --git a/lib/telegram/bot/updates_controller/typed_update.rb b/lib/telegram/bot/updates_controller/typed_update.rb
index 78fd985..0cc1aa7 100644
--- a/lib/telegram/bot/updates_controller/typed_update.rb
+++ b/lib/telegram/bot/updates_controller/typed_update.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Telegram
   module Bot
     class UpdatesController
diff --git a/lib/telegram/bot/updates_poller.rb b/lib/telegram/bot/updates_poller.rb
index c39088c..7b43e86 100644
--- a/lib/telegram/bot/updates_poller.rb
+++ b/lib/telegram/bot/updates_poller.rb
@@ -1,9 +1,11 @@
+# frozen_string_literal: true
+
 module Telegram
   module Bot
     # Supposed to be used in development environments only.
     class UpdatesPoller
       class << self
-        @@instances = {} # rubocop:disable ClassVars
+        @@instances = {} # rubocop:disable Style/ClassVars
 
         def instances
           @@instances
@@ -36,7 +38,7 @@ module Telegram
       end
 
       def log(&block)
-        logger.info(&block) if logger
+        logger&.info(&block)
       end
 
       def start
@@ -56,7 +58,7 @@ module Telegram
       def run
         while running
           updates = fetch_updates
-          process_updates(updates) if updates && updates.any?
+          process_updates(updates) if updates&.any?
         end
       end
 
@@ -82,8 +84,8 @@ module Telegram
             process_update(update)
           end
         end
-      rescue StandardError => e
-        logger.error { ([e.message] + e.backtrace).join("\n") } if logger
+      rescue StandardError => exception
+        logger&.error { ([exception.message] + exception.backtrace).join("\n") }
       end
 
       # Override this method to setup custom error collector.
@@ -102,10 +104,8 @@ module Telegram
       end
 
       if defined?(Rails.application) && Rails.application.respond_to?(:reloader)
-        def reloading_code
-          Rails.application.reloader.wrap do
-            yield
-          end
+        def reloading_code(&block)
+          Rails.application.reloader.wrap(&block)
         end
       else
         def reloading_code
diff --git a/lib/telegram/bot/version.rb b/lib/telegram/bot/version.rb
index d678e4f..48a9a2e 100644
--- a/lib/telegram/bot/version.rb
+++ b/lib/telegram/bot/version.rb
@@ -1,6 +1,8 @@
+# frozen_string_literal: true
+
 module Telegram
   module Bot
-    VERSION = '0.16.1'.freeze
+    VERSION = '0.16.1'
 
     def self.gem_version
       Gem::Version.new VERSION
diff --git a/spec/integration/requests/default_bot_spec.rb b/spec/integration/requests/default_bot_spec.rb
index 0f7feed..1ef5753 100644
--- a/spec/integration/requests/default_bot_spec.rb
+++ b/spec/integration/requests/default_bot_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'integration_helper'
 
 RSpec.describe DefaultBotController, telegram_bot: :rails do
diff --git a/spec/integration/requests/named_bot_spec.rb b/spec/integration/requests/named_bot_spec.rb
index cccfbd4..0be5575 100644
--- a/spec/integration/requests/named_bot_spec.rb
+++ b/spec/integration/requests/named_bot_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'integration_helper'
 
 RSpec.describe NamedBotController, telegram_bot: :rails do
diff --git a/spec/integration/requests/other_bot_spec.rb b/spec/integration/requests/other_bot_spec.rb
index 8ccb783..babd569 100644
--- a/spec/integration/requests/other_bot_spec.rb
+++ b/spec/integration/requests/other_bot_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'integration_helper'
 
 RSpec.describe OtherBotController, telegram_bot: :rails do
diff --git a/spec/integration_helper.rb b/spec/integration_helper.rb
index e876124..2bb0796 100644
--- a/spec/integration_helper.rb
+++ b/spec/integration_helper.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'telegram/bot/rspec/integration/rails'
 require 'action_controller'
 require 'action_dispatch'
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 1be5648..36471a5 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'pathname'
 require 'pry'
 require 'rspec/its'
@@ -10,7 +12,7 @@ elsif ENV.key?('COV')
   SimpleCov.start
 end
 
-GEM_ROOT = Pathname.new File.expand_path('../..', __FILE__)
+GEM_ROOT = Pathname.new File.expand_path('..', __dir__)
 
 $LOAD_PATH.unshift GEM_ROOT.join('lib')
 require 'telegram/bot'
@@ -18,7 +20,7 @@ require 'telegram/bot/updates_controller/rspec_helpers'
 require 'telegram/bot/types'
 require 'active_support/json'
 
-Dir[GEM_ROOT.join('spec/support/**/*.rb')].each { |f| require f }
+Dir[GEM_ROOT.join('spec/support/**/*.rb')].sort.each { |f| require f }
 
 RSpec.configure do |config|
   config.expect_with :rspec do |expectations|
diff --git a/spec/support/examples/async.rb b/spec/support/examples/async.rb
index 683a01e..91fb1b3 100644
--- a/spec/support/examples/async.rb
+++ b/spec/support/examples/async.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 RSpec.shared_examples 'async' do |request_args:|
   let(:instance) { described_class.new(token: token, id: id, async: async) }
   let(:id) { :default_bot }
diff --git a/spec/support/examples/integration.rb b/spec/support/examples/integration.rb
index cb79400..0f78553 100644
--- a/spec/support/examples/integration.rb
+++ b/spec/support/examples/integration.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 RSpec.shared_examples 'shared integration examples' do
   let(:bot) { Telegram::Bot::ClientStub.new('token') }
   let(:controller_class) do
diff --git a/spec/telegram/bot/async_spec.rb b/spec/telegram/bot/async_spec.rb
index ce13e43..216aeec 100644
--- a/spec/telegram/bot/async_spec.rb
+++ b/spec/telegram/bot/async_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 RSpec.describe Telegram::Bot::Async::Job do
   let(:job_class) do
     described_class = self.described_class
diff --git a/spec/telegram/bot/client/request_body_formatter_spec.rb b/spec/telegram/bot/client/request_body_formatter_spec.rb
index 35a1e6a..35f5134 100644
--- a/spec/telegram/bot/client/request_body_formatter_spec.rb
+++ b/spec/telegram/bot/client/request_body_formatter_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 RSpec.describe Telegram::Bot::Client::RequestBodyFormatter do
   describe '.format' do
     subject { described_class.format(input, action) }
diff --git a/spec/telegram/bot/client/typed_response_spec.rb b/spec/telegram/bot/client/typed_response_spec.rb
index d8eb476..681d336 100644
--- a/spec/telegram/bot/client/typed_response_spec.rb
+++ b/spec/telegram/bot/client/typed_response_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 RSpec.describe Telegram::Bot::Client::TypedResponse do
   let(:bot) { Telegram::Bot::Client.new('token').tap { |x| x.extend described_class } }
 
diff --git a/spec/telegram/bot/client_spec.rb b/spec/telegram/bot/client_spec.rb
index e787ba0..2b1e769 100644
--- a/spec/telegram/bot/client_spec.rb
+++ b/spec/telegram/bot/client_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 RSpec.describe Telegram::Bot::Client do
   let(:instance) { described_class.new 'token' }
   let(:token) { 'token' }
@@ -73,8 +75,8 @@ RSpec.describe Telegram::Bot::Client do
 
   describe '.prepare_async_args' do
     subject { described_class.prepare_async_args(*input) }
-    let(:input) { [:action, a: 1, b: :sym, c: [:other], 'd' => 'str'] }
-    it { should eq ['action', a: 1, b: 'sym', c: '["other"]', 'd' => 'str'] }
+    let(:input) { [:action, {a: 1, b: :sym, c: [:other], 'd' => 'str'}] }
+    it { should eq ['action', {a: 1, b: 'sym', c: '["other"]', 'd' => 'str'}] }
   end
 
   describe '.new' do
diff --git a/spec/telegram/bot/client_stub_spec.rb b/spec/telegram/bot/client_stub_spec.rb
index 655ad08..4d2dfdb 100644
--- a/spec/telegram/bot/client_stub_spec.rb
+++ b/spec/telegram/bot/client_stub_spec.rb
@@ -1,7 +1,9 @@
+# frozen_string_literal: true
+
 RSpec.describe Telegram::Bot::ClientStub do
   describe '#stub_all!' do
     let(:client) { Telegram::Bot::Client.new('token', 'bot_name') }
-    let(:clients) { ['token', token: 'token2'].map(&Telegram::Bot::Client.method(:wrap)) }
+    let(:clients) { ['token', {token: 'token2'}].map(&Telegram::Bot::Client.method(:wrap)) }
 
     shared_examples 'constructors' do |expected_class|
       it 'makes Client.new return ClientStub' do
diff --git a/spec/telegram/bot/config_methods_spec.rb b/spec/telegram/bot/config_methods_spec.rb
index e8acd96..e946378 100644
--- a/spec/telegram/bot/config_methods_spec.rb
+++ b/spec/telegram/bot/config_methods_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 RSpec.describe Telegram::Bot::ConfigMethods do
   let(:registry) do
     Object.new.tap do |x|
diff --git a/spec/telegram/bot/middleware_spec.rb b/spec/telegram/bot/middleware_spec.rb
index 3a465bf..88704b8 100644
--- a/spec/telegram/bot/middleware_spec.rb
+++ b/spec/telegram/bot/middleware_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'rack/mock'
 
 RSpec.describe Telegram::Bot::Middleware do
@@ -11,7 +13,7 @@ RSpec.describe Telegram::Bot::Middleware do
     let(:env) do
       Rack::MockRequest.env_for('/',
         method: :post,
-        input:  JSON.dump(update),
+        input: JSON.dump(update),
         'CONTENT_TYPE' => 'application/json',
       )
     end
diff --git a/spec/telegram/bot/routes_helper_spec.rb b/spec/telegram/bot/routes_helper_spec.rb
index ed9049b..55b8e4c 100644
--- a/spec/telegram/bot/routes_helper_spec.rb
+++ b/spec/telegram/bot/routes_helper_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'telegram/bot/routes_helper'
 
 RSpec.describe Telegram::Bot::RoutesHelper do
@@ -46,7 +48,7 @@ RSpec.describe Telegram::Bot::RoutesHelper do
     let(:controller) { double(:controller, name: :controller) }
     before { allow(Telegram).to receive(:bots) { bots } }
 
-    def assert_route(bot, controller, path: nil, **expected_options) # rubocop:disable AbcSize
+    def assert_route(bot, controller, path: nil, **expected_options) # rubocop:disable Metrics/AbcSize
       path ||= "telegram/#{described_class.token_hash(bot.token)}"
       expect(mapper).to receive(:post) do |actual_path, actual_options|
         expect(actual_path).to eq(path)
diff --git a/spec/telegram/bot/rspec/callback_query_helpers_spec.rb b/spec/telegram/bot/rspec/callback_query_helpers_spec.rb
index f32397e..1820c2d 100644
--- a/spec/telegram/bot/rspec/callback_query_helpers_spec.rb
+++ b/spec/telegram/bot/rspec/callback_query_helpers_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'telegram/bot/rspec/integration/poller'
 
 RSpec.describe 'Integration spec helpers', telegram_bot: :poller do
diff --git a/spec/telegram/bot/rspec/client_matchers_spec.rb b/spec/telegram/bot/rspec/client_matchers_spec.rb
index 9292190..c441877 100644
--- a/spec/telegram/bot/rspec/client_matchers_spec.rb
+++ b/spec/telegram/bot/rspec/client_matchers_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 RSpec.describe Telegram::Bot::RSpec::ClientMatchers do
   let(:bot) { Telegram::Bot::ClientStub.new('TestBot') }
   let(:other_bot) { Telegram::Bot::ClientStub.new('OtherTestBot') }
diff --git a/spec/telegram/bot/rspec/integration/poller_spec.rb b/spec/telegram/bot/rspec/integration/poller_spec.rb
index c83723f..5e2d5a0 100644
--- a/spec/telegram/bot/rspec/integration/poller_spec.rb
+++ b/spec/telegram/bot/rspec/integration/poller_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'telegram/bot/rspec/integration/poller'
 
 RSpec.describe 'Poller integration spec', telegram_bot: :poller do
diff --git a/spec/telegram/bot/rspec/integration/rack_spec.rb b/spec/telegram/bot/rspec/integration/rack_spec.rb
index 0dcfb53..19a48fa 100644
--- a/spec/telegram/bot/rspec/integration/rack_spec.rb
+++ b/spec/telegram/bot/rspec/integration/rack_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'telegram/bot/rspec/integration/rack'
 
 RSpec.describe 'Rack integration spec', telegram_bot: :rack do
diff --git a/spec/telegram/bot/rspec/integration/rails_spec.rb b/spec/telegram/bot/rspec/integration/rails_spec.rb
index 05c498e..9796c07 100644
--- a/spec/telegram/bot/rspec/integration/rails_spec.rb
+++ b/spec/telegram/bot/rspec/integration/rails_spec.rb
@@ -1 +1,2 @@
+# frozen_string_literal: true
 # Tested in spec/integration
diff --git a/spec/telegram/bot/rspec/message_helpers_spec.rb b/spec/telegram/bot/rspec/message_helpers_spec.rb
index 63fb315..6781641 100644
--- a/spec/telegram/bot/rspec/message_helpers_spec.rb
+++ b/spec/telegram/bot/rspec/message_helpers_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'telegram/bot/rspec/integration/poller'
 
 RSpec.describe 'Integration: message helpers', telegram_bot: :poller do
@@ -108,7 +110,7 @@ RSpec.describe 'Integration: message helpers', telegram_bot: :poller do
     end
 
     context 'with options' do
-      let(:args) { ['asd', 'qwe', option: 1] }
+      let(:args) { ['asd', 'qwe', {option: 1}] }
       it { should respond_with_message "Start: #{args[0...-1].inspect}, option: 1" }
     end
   end
diff --git a/spec/telegram/bot/updates_controller/callback_query_context_spec.rb b/spec/telegram/bot/updates_controller/callback_query_context_spec.rb
index 757e939..3df25c1 100644
--- a/spec/telegram/bot/updates_controller/callback_query_context_spec.rb
+++ b/spec/telegram/bot/updates_controller/callback_query_context_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 RSpec.describe Telegram::Bot::UpdatesController::CallbackQueryContext do
   include_context 'telegram/bot/updates_controller'
   let(:controller_class) do
@@ -6,7 +8,8 @@ RSpec.describe Telegram::Bot::UpdatesController::CallbackQueryContext do
       include described_class
 
       attr_accessor :filter_done
-      before_action only: :ctx2_callback_query do
+
+      before_action only: :ctx_2_callback_query do
         self.filter_done = true
       end
 
@@ -14,12 +17,12 @@ RSpec.describe Telegram::Bot::UpdatesController::CallbackQueryContext do
         [:no_context, data]
       end
 
-      def ctx1_callback_query(data)
-        [:ctx1, data]
+      def ctx_1_callback_query(data)
+        [:ctx_1, data]
       end
 
-      def ctx2_callback_query(data)
-        [:ctx2, data]
+      def ctx_2_callback_query(data)
+        [:ctx_2, data]
       end
     end
   end
@@ -40,19 +43,19 @@ RSpec.describe Telegram::Bot::UpdatesController::CallbackQueryContext do
       let(:data) { "#{ctx}:#{text}" }
 
       context 'and valid' do
-        let(:ctx) { 'ctx1' }
-        its(:call) { should eq [:ctx1, text] }
+        let(:ctx) { 'ctx_1' }
+        its(:call) { should eq [:ctx_1, text] }
         it { should_not change(controller, :filter_done) }
 
         context 'and context has callback' do
-          let(:ctx) { 'ctx2' }
-          its(:call) { should eq [:ctx2, text] }
+          let(:ctx) { 'ctx_2' }
+          its(:call) { should eq [:ctx_2, text] }
           it { should change(controller, :filter_done) }
         end
 
         context 'and data has multiple colons' do
           let(:text) { super().tr(' ', ':') }
-          its(:call) { should eq [:ctx1, text] }
+          its(:call) { should eq [:ctx_1, text] }
         end
       end
 
diff --git a/spec/telegram/bot/updates_controller/commands_spec.rb b/spec/telegram/bot/updates_controller/commands_spec.rb
index 5dfb196..2416db3 100644
--- a/spec/telegram/bot/updates_controller/commands_spec.rb
+++ b/spec/telegram/bot/updates_controller/commands_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 RSpec.describe Telegram::Bot::UpdatesController::Commands do
   describe '#action_for_command' do
     subject { ->(*args) { object.action_for_command(*args) } }
@@ -88,11 +90,11 @@ RSpec.describe Telegram::Bot::UpdatesController::Commands do
         context 'with command' do
           let(:text) { "/test#{"@#{mention}" if mention} arg 1 2" }
           let(:mention) {}
-          it { should eq [['test!', type: :command, command: 'test'], %w[arg 1 2]] }
+          it { should eq [['test!', {type: :command, command: 'test'}], %w[arg 1 2]] }
 
           context 'with mention' do
             let(:mention) { bot.username }
-            it { should eq [['test!', type: :command, command: 'test'], %w[arg 1 2]] }
+            it { should eq [['test!', {type: :command, command: 'test'}], %w[arg 1 2]] }
           end
 
           context 'with mention for other bot' do
diff --git a/spec/telegram/bot/updates_controller/instrumentation_spec.rb b/spec/telegram/bot/updates_controller/instrumentation_spec.rb
index cb0c190..8229bd9 100644
--- a/spec/telegram/bot/updates_controller/instrumentation_spec.rb
+++ b/spec/telegram/bot/updates_controller/instrumentation_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 RSpec.describe Telegram::Bot::UpdatesController::Instrumentation do
   include_context 'telegram/bot/updates_controller'
 
diff --git a/spec/telegram/bot/updates_controller/message_context_spec.rb b/spec/telegram/bot/updates_controller/message_context_spec.rb
index 9ab4952..2d233d0 100644
--- a/spec/telegram/bot/updates_controller/message_context_spec.rb
+++ b/spec/telegram/bot/updates_controller/message_context_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 RSpec.describe Telegram::Bot::UpdatesController::MessageContext do
   include_context 'telegram/bot/updates_controller'
   let(:controller_class) do
@@ -6,11 +8,13 @@ RSpec.describe Telegram::Bot::UpdatesController::MessageContext do
       include described_class
 
       attr_accessor :filter_done
+
       before_action only: :context_with_filter do
         self.filter_done = true
       end
 
       attr_reader :callbacks_runs
+
       before_action { @callbacks_runs = (@callbacks_runs || 0) + 1 }
 
       def message(*args)
diff --git a/spec/telegram/bot/updates_controller/reply_helpers_spec.rb b/spec/telegram/bot/updates_controller/reply_helpers_spec.rb
index e5ad3b8..2577adc 100644
--- a/spec/telegram/bot/updates_controller/reply_helpers_spec.rb
+++ b/spec/telegram/bot/updates_controller/reply_helpers_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 RSpec.describe Telegram::Bot::UpdatesController do
   include_context 'telegram/bot/updates_controller'
   let(:params) { {arg: 1, 'other_arg' => 2} }
@@ -38,7 +40,7 @@ RSpec.describe Telegram::Bot::UpdatesController do
     end
 
     context 'when update is not set' do
-      let(:controller_args) { [bot, chat: deep_stringify(chat)] }
+      let(:controller_args) { [bot, {chat: deep_stringify(chat)}] }
       it 'sets chat_id' do
         expect(bot).to receive("send_#{respond_type}").
           with(params.merge(chat_id: chat[:id])) { result }
diff --git a/spec/telegram/bot/updates_controller/rescue_spec.rb b/spec/telegram/bot/updates_controller/rescue_spec.rb
index d7dd275..8ff5a6e 100644
--- a/spec/telegram/bot/updates_controller/rescue_spec.rb
+++ b/spec/telegram/bot/updates_controller/rescue_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 RSpec.describe Telegram::Bot::UpdatesController::Rescue do
   include_context 'telegram/bot/updates_controller'
 
diff --git a/spec/telegram/bot/updates_controller/session_spec.rb b/spec/telegram/bot/updates_controller/session_spec.rb
index 8bb092a..ec2c804 100644
--- a/spec/telegram/bot/updates_controller/session_spec.rb
+++ b/spec/telegram/bot/updates_controller/session_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 RSpec.describe Telegram::Bot::UpdatesController::Session do
   include_context 'telegram/bot/updates_controller'
   let(:controller_class) do
diff --git a/spec/telegram/bot/updates_controller/testing_spec.rb b/spec/telegram/bot/updates_controller/testing_spec.rb
index fcc4fe1..398adc5 100644
--- a/spec/telegram/bot/updates_controller/testing_spec.rb
+++ b/spec/telegram/bot/updates_controller/testing_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'action_dispatch'
 
 RSpec.describe Telegram::Bot::UpdatesController::Testing do
@@ -43,7 +45,7 @@ RSpec.describe Telegram::Bot::UpdatesController::Testing do
 
     context 'when webhook_request is given' do
       it 'passes it to controller' do
-        webhook_request = ::ActionDispatch::Request.new({})
+        webhook_request = ActionDispatch::Request.new({})
         dispatch(update, bot, webhook_request)
         expect(controller.webhook_request).to eq webhook_request
       end
diff --git a/spec/telegram/bot/updates_controller/translation_spec.rb b/spec/telegram/bot/updates_controller/translation_spec.rb
index 3368527..991c11c 100644
--- a/spec/telegram/bot/updates_controller/translation_spec.rb
+++ b/spec/telegram/bot/updates_controller/translation_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 RSpec.describe Telegram::Bot::UpdatesController::Translation do
   def self.stub_translations(translations)
     around do |ex|
diff --git a/spec/telegram/bot/updates_controller/typed_update_spec.rb b/spec/telegram/bot/updates_controller/typed_update_spec.rb
index c74586c..877ce3b 100644
--- a/spec/telegram/bot/updates_controller/typed_update_spec.rb
+++ b/spec/telegram/bot/updates_controller/typed_update_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 RSpec.describe Telegram::Bot::UpdatesController::TypedUpdate do
   include_context 'telegram/bot/updates_controller'
   let(:controller_class) do
diff --git a/spec/telegram/bot/updates_controller_spec.rb b/spec/telegram/bot/updates_controller_spec.rb
index e7e3860..3007ac5 100644
--- a/spec/telegram/bot/updates_controller_spec.rb
+++ b/spec/telegram/bot/updates_controller_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 RSpec.describe Telegram::Bot::UpdatesController do
   include_context 'telegram/bot/updates_controller'
 
@@ -5,7 +7,7 @@ RSpec.describe Telegram::Bot::UpdatesController do
     subject { controller.action_for_payload }
 
     def stub_payload(*fields)
-      Hash[fields.map { |x| [x, double(x)] }]
+      fields.map { |x| [x, double(x)] }.to_h
     end
 
     context 'when payload is inline_query' do
@@ -90,7 +92,7 @@ RSpec.describe Telegram::Bot::UpdatesController do
 
   describe '#process' do
     subject { -> { controller.process(:action, *args) } }
-    let(:args) { %i[arg1 arg2] }
+    let(:args) { %i[arg_1 arg_2] }
     let(:controller_class) do
       Class.new(described_class) do
         attr_reader :acted, :hooked
@@ -198,7 +200,7 @@ RSpec.describe Telegram::Bot::UpdatesController do
     end
 
     context 'when options hash is given' do
-      let(:controller_args) { [bot, from: from, chat: chat] }
+      let(:controller_args) { [bot, {from: from, chat: chat}] }
       with_reinitialize do
         its(:bot) { should eq bot }
         its(:update) { should eq nil }
diff --git a/spec/telegram/bot/updates_poller_spec.rb b/spec/telegram/bot/updates_poller_spec.rb
index 1a13bbb..aaa5177 100644
--- a/spec/telegram/bot/updates_poller_spec.rb
+++ b/spec/telegram/bot/updates_poller_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 RSpec.describe Telegram::Bot::UpdatesPoller do
   let(:instance) { described_class.new(bot, controller) }
   let(:bot) { Telegram::Bot::Client.new('token') }
diff --git a/spec/telegram/bot_spec.rb b/spec/telegram/bot_spec.rb
index 19a51f4..fd54622 100644
--- a/spec/telegram/bot_spec.rb
+++ b/spec/telegram/bot_spec.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 RSpec.describe Telegram::Bot do
   it 'has a version number' do
     expect(described_class::VERSION).not_to be nil
diff --git a/telegram-bot.gemspec b/telegram-bot.gemspec
index a71ca53..ae97f06 100644
--- a/telegram-bot.gemspec
+++ b/telegram-bot.gemspec
@@ -1,4 +1,6 @@
-lib = File.expand_path('../lib', __FILE__)
+# frozen_string_literal: true
+
+lib = File.expand_path('lib', __dir__)
 $LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
 require 'telegram/bot/version'
 
@@ -12,6 +14,10 @@ Gem::Specification.new do |spec|
   spec.homepage      = 'https://github.com/telegram-bot-rb/telegram-bot'
   spec.license       = 'MIT'
 
+  spec.metadata      = {
+    'rubygems_mfa_required' => 'true',
+  }
+
   spec.files         = `git ls-files -z`.split("\x0").reject { |f| f.match(%r{^spec/}) }
   spec.bindir        = 'exe'
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }