diff --git a/.codeclimate.yml b/.codeclimate.yml
index 9d83f9d..3194faa 100644
--- a/.codeclimate.yml
+++ b/.codeclimate.yml
@@ -7,7 +7,7 @@ checks:
 plugins:
   rubocop:
     enabled: true
-    channel: rubocop-1-11
+    channel: rubocop-1-12
 
   reek:
     enabled: true
diff --git a/.rubocop.yml b/.rubocop.yml
index 90bfcdb..236f374 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -151,6 +151,9 @@ Style/IfWithBooleanLiteralBranches:
 Style/HashConversion:
   Enabled: true
 
+Style/StringChars:
+  Enabled: true
+
 Layout/LineLength:
   Max: 140
 
diff --git a/CHANGELOG.md b/CHANGELOG.md
index e77aa8a..c207847 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,14 @@
 
 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).
 
+## [2.3.3] - 2021.04.14
+
+### Changed
+
+- Updated gem development dependencies
+- Updated rubocop/codeclimate config
+- Updated CircleCI config
+
 ## [2.3.2] - 2021.03.08
 
 ### Changed
diff --git a/Gemfile.lock b/Gemfile.lock
index ce967a3..9da605f 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    truemail (2.3.2)
+    truemail (2.3.3)
       simpleidn (~> 0.2.1)
 
 GEM
@@ -10,9 +10,9 @@ GEM
     addressable (2.7.0)
       public_suffix (>= 2.0.2, < 5.0)
     ast (2.4.2)
-    bundler-audit (0.7.0.1)
+    bundler-audit (0.8.0)
       bundler (>= 1.2.0, < 3)
-      thor (>= 0.18, < 2)
+      thor (~> 1.0)
     byebug (11.1.3)
     childprocess (4.0.0)
     coderay (1.1.3)
@@ -21,15 +21,15 @@ GEM
     crack (0.4.5)
       rexml
     diff-lcs (1.4.4)
-    dns_mock (1.2.0)
+    dns_mock (1.2.1)
     docile (1.3.5)
-    faker (2.16.0)
+    faker (2.17.0)
       i18n (>= 1.6, < 2)
     fasterer (0.9.0)
       colorize (~> 0.7)
       ruby_parser (>= 3.14.1)
     hashdiff (1.0.1)
-    i18n (1.8.9)
+    i18n (1.8.10)
       concurrent-ruby (~> 1.0)
     iniparse (1.5.0)
     json (2.5.1)
@@ -42,7 +42,7 @@ GEM
       childprocess (>= 0.6.3, < 5)
       iniparse (~> 1.4)
     parallel (1.20.1)
-    parser (3.0.0.0)
+    parser (3.0.1.0)
       ast (~> 2.4.1)
     pry (0.13.1)
       coderay (~> 1.1)
@@ -60,7 +60,7 @@ GEM
       psych (~> 3.1)
       rainbow (>= 2.0, < 4.0)
     regexp_parser (2.1.1)
-    rexml (3.2.4)
+    rexml (3.2.5)
     rspec (3.10.0)
       rspec-core (~> 3.10.0)
       rspec-expectations (~> 3.10.0)
@@ -74,7 +74,7 @@ GEM
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.10.0)
     rspec-support (3.10.2)
-    rubocop (1.11.0)
+    rubocop (1.12.1)
       parallel (~> 1.10)
       parser (>= 3.0.0.0)
       rainbow (>= 2.2.2, < 4.0)
@@ -85,7 +85,7 @@ GEM
       unicode-display_width (>= 1.4.0, < 3.0)
     rubocop-ast (1.4.1)
       parser (>= 2.7.1.5)
-    rubocop-performance (1.10.1)
+    rubocop-performance (1.10.2)
       rubocop (>= 0.90.0, < 2.0)
       rubocop-ast (>= 0.4.0)
     rubocop-rspec (2.2.0)
@@ -111,7 +111,7 @@ GEM
       unf_ext
     unf_ext (0.0.7.7)
     unicode-display_width (2.0.0)
-    webmock (3.12.1)
+    webmock (3.12.2)
       addressable (>= 2.3.6)
       crack (>= 0.3.2)
       hashdiff (>= 0.4.0, < 2.0.0)
@@ -121,9 +121,9 @@ PLATFORMS
 
 DEPENDENCIES
   bundler (~> 1.16)
-  bundler-audit (~> 0.7.0.1)
-  dns_mock (~> 1.2)
-  faker (~> 2.16)
+  bundler-audit (~> 0.8.0)
+  dns_mock (~> 1.2, >= 1.2.1)
+  faker (~> 2.17)
   fasterer (~> 0.9.0)
   json_matchers (~> 0.11.1)
   overcommit (~> 0.57.0)
@@ -131,13 +131,13 @@ DEPENDENCIES
   rake (~> 13.0, >= 13.0.3)
   reek (~> 6.0, >= 6.0.3)
   rspec (~> 3.10)
-  rubocop (~> 1.11)
-  rubocop-performance (~> 1.10, >= 1.10.1)
+  rubocop (~> 1.12, >= 1.12.1)
+  rubocop-performance (~> 1.10, >= 1.10.2)
   rubocop-rspec (~> 2.2)
   simplecov (~> 0.17.1)
   truemail!
   truemail-rspec (~> 0.4)
-  webmock (~> 3.12, >= 3.12.1)
+  webmock (~> 3.12, >= 3.12.2)
 
 BUNDLED WITH
    1.16.6
diff --git a/.circleci/config.yml b/circle.yml
similarity index 78%
rename from .circleci/config.yml
rename to circle.yml
index 83be873..2b8babe 100644
--- a/.circleci/config.yml
+++ b/circle.yml
@@ -1,3 +1,5 @@
+version: 2.1
+
 defaults: &defaults
   working_directory: ~/truemail
   docker:
@@ -5,6 +7,9 @@ defaults: &defaults
   environment:
     CC_TEST_REPORTER_ID: 693272a1328521f6f7c09d7ffd419b21c00410da26e98e94c687fdd38b26e2cb
 
+orbs:
+  ruby: circleci/ruby@1.1.2
+
 references:
   restore_bundle_cache: &restore_bundle_cache
     restore_cache:
@@ -29,7 +34,6 @@ references:
             curl -L https://codeclimate.com/downloads/test-reporter/test-reporter-latest-linux-amd64 > ./cc-test-reporter
             chmod +x ./cc-test-reporter
 
-version: 2
 jobs:
   linters:
     <<: *defaults
@@ -81,9 +85,28 @@ jobs:
           command: |
             ./cc-test-reporter sum-coverage --output - --parts $CIRCLE_NODE_TOTAL coverage/codeclimate.*.json | ./cc-test-reporter upload-coverage --debug --input -
 
+  compatibility-with-ruby:
+    parameters:
+      ruby-version:
+        type: string
+    docker:
+      - image: cimg/ruby:<< parameters.ruby-version >>
+    steps:
+      - checkout
+      - ruby/install-deps:
+          bundler-version: '1.16.6'
+          with-cache: false
+          path: './vendor/custom_bundle'
+      - run:
+          name: Running compatibility tests
+          command: bundle exec rspec
+
 workflows:
-  version: 2
-  build:
+  build_and_test:
     jobs:
       - linters
       - tests
+      - compatibility-with-ruby:
+          matrix:
+            parameters:
+              ruby-version: ["2.6", "2.7", "3.0"]
diff --git a/lib/truemail/version.rb b/lib/truemail/version.rb
index 2bdbab4..06e8526 100644
--- a/lib/truemail/version.rb
+++ b/lib/truemail/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Truemail
-  VERSION = '2.3.2'
+  VERSION = '2.3.3'
 end
diff --git a/truemail.gemspec b/truemail.gemspec
index c0a8f72..af880f7 100644
--- a/truemail.gemspec
+++ b/truemail.gemspec
@@ -34,9 +34,9 @@ Gem::Specification.new do |spec|
   spec.add_runtime_dependency 'simpleidn', '~> 0.2.1'
 
   spec.add_development_dependency 'bundler', '~> 1.16'
-  spec.add_development_dependency 'bundler-audit', '~> 0.7.0.1'
-  spec.add_development_dependency 'dns_mock', '~> 1.2'
-  spec.add_development_dependency 'faker', '~> 2.16'
+  spec.add_development_dependency 'bundler-audit', '~> 0.8.0'
+  spec.add_development_dependency 'dns_mock', '~> 1.2', '>= 1.2.1'
+  spec.add_development_dependency 'faker', '~> 2.17'
   spec.add_development_dependency 'fasterer', '~> 0.9.0'
   spec.add_development_dependency 'json_matchers', '~> 0.11.1'
   spec.add_development_dependency 'overcommit', '~> 0.57.0'
@@ -44,10 +44,10 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'rake', '~> 13.0', '>= 13.0.3'
   spec.add_development_dependency 'reek', '~> 6.0', '>= 6.0.3'
   spec.add_development_dependency 'rspec', '~> 3.10'
-  spec.add_development_dependency 'rubocop', '~> 1.11'
-  spec.add_development_dependency 'rubocop-performance', '~> 1.10', '>= 1.10.1'
+  spec.add_development_dependency 'rubocop', '~> 1.12', '>= 1.12.1'
+  spec.add_development_dependency 'rubocop-performance', '~> 1.10', '>= 1.10.2'
   spec.add_development_dependency 'rubocop-rspec', '~> 2.2'
   spec.add_development_dependency 'simplecov', '~> 0.17.1'
   spec.add_development_dependency 'truemail-rspec', '~> 0.4'
-  spec.add_development_dependency 'webmock', '~> 3.12', '>= 3.12.1'
+  spec.add_development_dependency 'webmock', '~> 3.12', '>= 3.12.2'
 end