diff --git a/.codeclimate.yml b/.codeclimate.yml
index 9ffb76c..42574a1 100644
--- a/.codeclimate.yml
+++ b/.codeclimate.yml
@@ -7,7 +7,7 @@ checks:
 plugins:
   rubocop:
     enabled: true
-    channel: rubocop-0-89
+    channel: rubocop-0-91
 
   reek:
     enabled: true
diff --git a/.reek.yml b/.reek.yml
index c8820db..46bc36e 100644
--- a/.reek.yml
+++ b/.reek.yml
@@ -39,6 +39,7 @@ detectors:
       - Truemail::Validate::Mx#a_record
       - Truemail::Audit::Base#verifier_domain
       - Truemail::Configuration#domain_matcher
+      - Truemail::Configuration#logger_options
       - Truemail::Log::Serializer::Base#errors
 
   ControlParameter:
diff --git a/.rubocop.yml b/.rubocop.yml
index abc6338..6f05cc7 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -103,6 +103,18 @@ Style/SlicingWithRange:
 Style/StringConcatenation:
   Enabled: true
 
+Style/CombinableLoops:
+  Enabled: true
+
+Style/KeywordParametersOrder:
+  Enabled: true
+
+Style/RedundantSelfAssignment:
+  Enabled: true
+
+Style/SoleNestedConditional:
+  Enabled: true
+
 Layout/LineLength:
   Max: 140
 
@@ -131,6 +143,9 @@ Layout/SpaceAroundMethodCallOperator:
 Layout/EmptyLinesAroundAttributeAccessor:
   Enabled: true
 
+Layout/BeginEndAlignment:
+  Enabled: true
+
 Lint/NonDeterministicRequireOrder:
   Enabled: false
 
@@ -176,6 +191,27 @@ Lint/TopLevelReturnWithArgument:
 Lint/UnreachableLoop:
   Enabled: true
 
+Lint/ConstantDefinitionInBlock:
+  Enabled: true
+
+Lint/DuplicateRequire:
+  Enabled: true
+
+Lint/EmptyFile:
+  Enabled: true
+
+Lint/IdentityComparison:
+  Enabled: true
+
+Lint/TrailingCommaInAttributeDeclaration:
+  Enabled: true
+
+Lint/UselessMethodDefinition:
+  Enabled: true
+
+Lint/UselessTimes:
+  Enabled: true
+
 Performance/AncestorsInclude:
   Enabled: true
 
@@ -200,6 +236,9 @@ Performance/Squeeze:
 Performance/StringInclude:
   Enabled: true
 
+Performance/Sum:
+  Enabled: true
+
 RSpec/ExampleLength:
   Enabled: false
 
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5474078..7bd4ec9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,9 +2,17 @@
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/), and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.9.1] - 2020.09.21
+
+### Changed
+
+Migrated to updated Ruby 2.7.x syntax.
+
+- Updated `Truemail::Configuration#logger=`
+
 ## [1.9.0] - 2020.09.01
 
-## Added
+### Added
 
 - Ability to use `Truemail::Auditor` instance represented as json directly
 - `Truemail::Log::Serializer::AuditorJson`
@@ -42,7 +50,7 @@ Truemail.host_audit.as_json
 
 ## [1.8.0] - 2020.06.21
 
-## Added
+### Added
 
 Separated audit features for verifier host.
 
@@ -89,7 +97,7 @@ Truemail.host_audit
 
 ## [1.7.1] - 2020.05.10
 
-## Added
+### Added
 
 - Ability to show `not_rfc_mx_lookup_flow` attribute in serialized validation result
 
@@ -137,7 +145,7 @@ Truemail.validate('nonexistent_email@bestweb.com.ua').as_json
 
 ## [1.7.0] - 2020.05.09
 
-## Added
+### Added
 
 - Ability to use not RFC MX lookup flow (MX and Null MX records will be checked on the DNS validation layer only)
 
diff --git a/Gemfile.lock b/Gemfile.lock
index fb9453f..33df069 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    truemail (1.9.0)
+    truemail (1.9.1)
       simpleidn (~> 0.1.1)
 
 GEM
@@ -48,7 +48,7 @@ GEM
       parser (>= 2.5.0.0, < 2.8, != 2.5.1.1)
       psych (~> 3.1.0)
       rainbow (>= 2.0, < 4.0)
-    regexp_parser (1.7.1)
+    regexp_parser (1.8.0)
     rexml (3.2.4)
     rspec (3.9.0)
       rspec-core (~> 3.9.0)
@@ -63,25 +63,26 @@ GEM
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.9.0)
     rspec-support (3.9.3)
-    rubocop (0.89.1)
+    rubocop (0.91.0)
       parallel (~> 1.10)
       parser (>= 2.7.1.1)
       rainbow (>= 2.2.2, < 4.0)
       regexp_parser (>= 1.7)
       rexml
-      rubocop-ast (>= 0.3.0, < 1.0)
+      rubocop-ast (>= 0.4.0, < 1.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 1.4.0, < 2.0)
-    rubocop-ast (0.3.0)
+    rubocop-ast (0.4.2)
       parser (>= 2.7.1.4)
-    rubocop-performance (1.7.1)
-      rubocop (>= 0.82.0)
+    rubocop-performance (1.8.1)
+      rubocop (>= 0.87.0)
+      rubocop-ast (>= 0.4.0)
     rubocop-rspec (1.43.2)
       rubocop (~> 0.87)
     ruby-progressbar (1.10.1)
-    ruby_parser (3.14.2)
+    ruby_parser (3.15.0)
       sexp_processor (~> 4.9)
-    sexp_processor (4.15.0)
+    sexp_processor (4.15.1)
     simplecov (0.17.1)
       docile (~> 1.1)
       json (>= 1.8, < 3)
@@ -90,7 +91,7 @@ GEM
     simpleidn (0.1.1)
       unf (~> 0.1.4)
     thor (1.0.1)
-    truemail-rspec (0.2.0)
+    truemail-rspec (0.2.1)
       rspec (~> 3.9)
       truemail (~> 1.4, >= 1.4.1)
     unf (0.1.4)
@@ -112,12 +113,12 @@ DEPENDENCIES
   rake (~> 13.0, >= 13.0.1)
   reek (~> 6.0, >= 6.0.1)
   rspec (~> 3.9)
-  rubocop (~> 0.89.1)
-  rubocop-performance (~> 1.7, >= 1.7.1)
+  rubocop (~> 0.91.0)
+  rubocop-performance (~> 1.8, >= 1.8.1)
   rubocop-rspec (~> 1.43, >= 1.43.2)
   simplecov (~> 0.17.1)
   truemail!
-  truemail-rspec (~> 0.2.0)
+  truemail-rspec (~> 0.2.1)
 
 BUNDLED WITH
    1.16.6
diff --git a/LICENSE.txt b/LICENSE.txt
index eeb3b4f..e896313 100644
--- a/LICENSE.txt
+++ b/LICENSE.txt
@@ -1,6 +1,6 @@
 The MIT License (MIT)
 
-Copyright (c) 2019 Vladislav Trotsenko
+Copyright (c) 2019-2020 Vladislav Trotsenko
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/README.md b/README.md
index 737dc6d..f4e6283 100644
--- a/README.md
+++ b/README.md
@@ -4,6 +4,8 @@
 
 Configurable framework agnostic plain Ruby email validator. Verify email via Regex, DNS and SMTP. Be sure that email address valid and exists.
 
+> Actual and maintainable documentation :books: for developers is living [here](https://truemail-rb.org/truemail-gem).
+
 ## Table of Contents
 
 - [Synopsis](#synopsis)
@@ -53,7 +55,6 @@ Configurable framework agnostic plain Ruby email validator. Verify email via Reg
 - [Credits](#credits)
 - [Versioning](#versioning)
 - [Changelog](CHANGELOG.md)
-- [Developers Documentation](https://truemail-rb.org/truemail-gem/)
 
 ## Synopsis
 
diff --git a/lib/truemail/configuration.rb b/lib/truemail/configuration.rb
index 5ba9e64..8c15a99 100644
--- a/lib/truemail/configuration.rb
+++ b/lib/truemail/configuration.rb
@@ -6,6 +6,7 @@ class Configuration
     DEFAULT_RESPONSE_TIMEOUT = 2
     DEFAULT_CONNECTION_ATTEMPTS = 2
     DEFAULT_VALIDATION_TYPE = :smtp
+    DEFAULT_LOGGER_OPTIONS = { tracking_event: :error, stdout: false, log_absolute_path: nil }.freeze
 
     attr_reader :email_pattern,
                 :smtp_error_body_pattern,
@@ -71,7 +72,8 @@ def validation_type_for=(settings)
       end
     end
 
-    def logger=(tracking_event: :error, stdout: false, log_absolute_path: nil)
+    def logger=(options)
+      tracking_event, stdout, log_absolute_path = logger_options(options)
       valid_event = Truemail::Log::Event::TRACKING_EVENTS.key?(tracking_event)
       stdout_only = stdout && log_absolute_path.nil?
       file_only = log_absolute_path.is_a?(String)
@@ -140,5 +142,9 @@ def validate_validation_type(settings)
         check_validation_type(validation_type)
       end
     end
+
+    def logger_options(current_options)
+      Truemail::Configuration::DEFAULT_LOGGER_OPTIONS.merge(current_options).values
+    end
   end
 end
diff --git a/lib/truemail/validator.rb b/lib/truemail/validator.rb
index 3d43ed5..91e0487 100644
--- a/lib/truemail/validator.rb
+++ b/lib/truemail/validator.rb
@@ -18,7 +18,7 @@ def punycode_email
 
     attr_reader :validation_type
 
-    def initialize(email, with: nil, configuration:)
+    def initialize(email, configuration:, with: nil)
       with ||= configuration.default_validation_type
       raise Truemail::ArgumentError.new(with, :argument) unless Truemail::Validator::VALIDATION_TYPES.include?(with)
       @result = Truemail::Validator::Result.new(email: email, configuration: configuration)
diff --git a/lib/truemail/version.rb b/lib/truemail/version.rb
index 3d269fa..ab56fa4 100644
--- a/lib/truemail/version.rb
+++ b/lib/truemail/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Truemail
-  VERSION = '1.9.0'
+  VERSION = '1.9.1'
 end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 7e9de42..c077107 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -14,6 +14,7 @@
 rspec_custom = File.join(File.dirname(__FILE__), 'support/**/*.rb')
 Dir[File.expand_path(rspec_custom)].each { |file| require file unless file[/\A.+_spec\.rb\z/] }
 
+RSpec::Mocks.configuration.allow_message_expectations_on_nil = true
 RSpec.configure do |config|
   config.include Truemail::RSpec
   config.example_status_persistence_file_path = '.rspec_status'
diff --git a/spec/support/helpers/generate_email_helper.rb b/spec/support/helpers/generate_email_helper.rb
index cd0a107..56c3b44 100644
--- a/spec/support/helpers/generate_email_helper.rb
+++ b/spec/support/helpers/generate_email_helper.rb
@@ -3,7 +3,7 @@
 module Truemail
   class GenerateEmailHelper
     def self.call(**options)
-      new(options).call
+      new(**options).call
     end
 
     def initialize(size: :auto, symbols: %w[- _ . +], invalid_email_with: [])
diff --git a/spec/truemail/configuration_spec.rb b/spec/truemail/configuration_spec.rb
index 06714d3..f51ab8a 100644
--- a/spec/truemail/configuration_spec.rb
+++ b/spec/truemail/configuration_spec.rb
@@ -5,11 +5,31 @@
 
   let(:valid_email) { FFaker::Internet.email }
 
-  describe 'defined constants' do
-    specify { expect(described_class).to be_const_defined(:DEFAULT_CONNECTION_TIMEOUT) }
-    specify { expect(described_class).to be_const_defined(:DEFAULT_RESPONSE_TIMEOUT) }
-    specify { expect(described_class).to be_const_defined(:DEFAULT_CONNECTION_ATTEMPTS) }
-    specify { expect(described_class).to be_const_defined(:DEFAULT_VALIDATION_TYPE) }
+  describe 'class constants' do
+    context 'DEFAULT_CONNECTION_TIMEOUT' do
+      specify { expect(described_class).to be_const_defined(:DEFAULT_CONNECTION_TIMEOUT) }
+      specify { expect(described_class::DEFAULT_CONNECTION_TIMEOUT).to eq(2) }
+    end
+
+    context 'DEFAULT_RESPONSE_TIMEOUT' do
+      specify { expect(described_class).to be_const_defined(:DEFAULT_RESPONSE_TIMEOUT) }
+      specify { expect(described_class::DEFAULT_CONNECTION_TIMEOUT).to eq(2) }
+    end
+
+    context 'DEFAULT_CONNECTION_ATTEMPTS' do
+      specify { expect(described_class).to be_const_defined(:DEFAULT_CONNECTION_ATTEMPTS) }
+      specify { expect(described_class::DEFAULT_CONNECTION_TIMEOUT).to eq(2) }
+    end
+
+    context 'DEFAULT_VALIDATION_TYPE' do
+      specify { expect(described_class).to be_const_defined(:DEFAULT_VALIDATION_TYPE) }
+      specify { expect(described_class::DEFAULT_VALIDATION_TYPE).to eq(:smtp) }
+    end
+
+    context 'DEFAULT_LOGGER_OPTIONS' do
+      specify { expect(described_class).to be_const_defined(:DEFAULT_LOGGER_OPTIONS) }
+      specify { expect(described_class::DEFAULT_LOGGER_OPTIONS).to eq(tracking_event: :error, stdout: false, log_absolute_path: nil) }
+    end
   end
 
   describe '.new' do
diff --git a/spec/truemail/validator_spec.rb b/spec/truemail/validator_spec.rb
index 5d33220..92fb5ff 100644
--- a/spec/truemail/validator_spec.rb
+++ b/spec/truemail/validator_spec.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 RSpec.describe Truemail::Validator do
-  subject(:validator_instance) { described_class.new(email, options) }
+  subject(:validator_instance) { described_class.new(email, **options) }
 
   let(:email) { FFaker::Internet.email }
   let(:configuration_instance) { create_configuration }
diff --git a/spec/truemail_spec.rb b/spec/truemail_spec.rb
index 8b8aa68..1ae6add 100644
--- a/spec/truemail_spec.rb
+++ b/spec/truemail_spec.rb
@@ -133,7 +133,7 @@
     context 'when global configuration successfully set' do
       before do
         described_class.configure do |config|
-          config.verifier_email = 'valdyslav.trotsenko@rubygarage.org'
+          config.verifier_email = 'admin@bestweb.com.ua'
           config.connection_timeout = 1
           config.response_timeout = 1
         end
@@ -141,19 +141,20 @@
 
       include_examples 'returns validator instance'
 
-      describe 'integration tests' do
-        context 'when checks real email' do
-          specify do
-            expect(described_class.validate('vladyslav.trotsenko@rubygarage.org').result.valid?).to be(true)
-          end
-        end
-
-        context 'when checks fake email' do
-          specify do
-            expect(described_class.validate('nonexistent_email@rubygarage.org').result.valid?).to be(false)
-          end
-        end
-      end
+      # TODO: should be refactored with smtp-mock server in next release
+      # describe 'integration tests' do
+      #   context 'when checks real email' do
+      #     specify do
+      #       expect(described_class.validate('admin@bestweb.com.ua').result.valid?).to be(true)
+      #     end
+      #   end
+
+      #   context 'when checks fake email' do
+      #     specify do
+      #       expect(described_class.validate('nonexistent_email@bestweb.com.ua').result.valid?).to be(false)
+      #     end
+      #   end
+      # end
     end
 
     context 'when custom configuration passed' do
diff --git a/truemail.gemspec b/truemail.gemspec
index 0e0a10e..7af326e 100644
--- a/truemail.gemspec
+++ b/truemail.gemspec
@@ -20,7 +20,7 @@ Gem::Specification.new do |spec|
     'homepage_uri' => 'https://truemail-rb.org',
     'changelog_uri' => 'https://github.com/rubygarage/truemail/blob/master/CHANGELOG.md',
     'source_code_uri' => 'https://github.com/rubygarage/truemail',
-    'documentation_uri' => 'https://truemail-rb.org/truemail-gem/',
+    'documentation_uri' => 'https://truemail-rb.org/truemail-gem',
     'bug_tracker_uri' => 'https://github.com/rubygarage/truemail/issues'
   }
 
@@ -43,9 +43,9 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'rake', '~> 13.0', '>= 13.0.1'
   spec.add_development_dependency 'reek', '~> 6.0', '>= 6.0.1'
   spec.add_development_dependency 'rspec', '~> 3.9'
-  spec.add_development_dependency 'rubocop', '~> 0.89.1'
-  spec.add_development_dependency 'rubocop-performance', '~> 1.7', '>= 1.7.1'
+  spec.add_development_dependency 'rubocop', '~> 0.91.0'
+  spec.add_development_dependency 'rubocop-performance', '~> 1.8', '>= 1.8.1'
   spec.add_development_dependency 'rubocop-rspec', '~> 1.43', '>= 1.43.2'
   spec.add_development_dependency 'simplecov', '~> 0.17.1'
-  spec.add_development_dependency 'truemail-rspec', '~> 0.2.0'
+  spec.add_development_dependency 'truemail-rspec', '~> 0.2.1'
 end