diff --git a/.circleci/config.yml b/.circleci/config.yml
index 9086601..6eacf84 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -55,11 +55,16 @@ jobs:
     docker:
       - image: circleci/ruby:2.5-node-browsers
       - image: circleci/mongo
-  build:
+  ruby-2.6:
     <<: *build_config
     docker:
       - image: circleci/ruby:2.6-node-browsers
       - image: circleci/mongo
+  ruby-2.7:
+    <<: *build_config
+    docker:
+      - image: circleci/ruby:2.7-node-browsers
+      - image: circleci/mongo
 
 workflows:
   version: 2
@@ -67,4 +72,5 @@ workflows:
     jobs:
       - ruby-2.4
       - ruby-2.5
-      - build
+      - ruby-2.6
+      - ruby-2.7
diff --git a/Appraisals b/Appraisals
index 14db46d..7fc457b 100644
--- a/Appraisals
+++ b/Appraisals
@@ -1,12 +1,25 @@
 # frozen_string_literal: true
 
-appraise 'sqlite3' do
-  gem 'rails', '~> 5.2'
-  gem 'sqlite3'
+appraise 'rails_5_2_sqlite3' do
+  gem 'rails', '5.2.4.4'
+  gem 'sqlite3', '~> 1.3.6'
 end
 
-appraise 'mongodb' do
-  gem 'rails', '~> 5.2'
-  gem 'mongoid'
-  gem 'bson_ext'
+if Gem::Requirement.new('>= 2.5.0').satisfied_by?(Gem::Version.new(RUBY_VERSION))
+  appraise 'rails_6_0_sqlite3' do
+    gem 'rails', '6.0.3.4'
+    gem 'sqlite3', '~> 1.4'
+  end
+end
+
+appraise 'rails_5_2_mongodb' do
+  gem 'rails', '5.2.4.4'
+  gem 'mongoid', '6.4'
+end
+
+if Gem::Requirement.new('>= 2.5.0').satisfied_by?(Gem::Version.new(RUBY_VERSION))
+  appraise 'rails_6_0_mongodb' do
+    gem 'rails', '6.0.3.4'
+    gem 'mongoid', '7.2'
+  end
 end
diff --git a/bin/setup b/bin/setup
index 44a17a1..f7a7c4f 100755
--- a/bin/setup
+++ b/bin/setup
@@ -6,8 +6,8 @@ set -e
 DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
 
 echo "Installing dependencies"
-gem install bundler --conservative
-bundle check || bundle install
+
+bundle check || bundle install --jobs=3 --retry=3
 
 bundle exec appraisal install
 
diff --git a/devise_2fa.gemspec b/devise_2fa.gemspec
index 51ea539..dd83dc1 100644
--- a/devise_2fa.gemspec
+++ b/devise_2fa.gemspec
@@ -18,7 +18,9 @@ Gem::Specification.new do |gem|
   gem.test_files    = gem.files.grep(%r{^(test|spec|features)/})
   gem.require_paths = ['lib']
 
-  gem.add_dependency "rails", ">= 4.1", "< 6.1"
+  gem.required_ruby_version = '>= 2.4.0'
+
+  gem.add_dependency 'rails', '>= 5', '< 6.1'
 
   gem.add_runtime_dependency 'devise', '~> 4.6'
   gem.add_runtime_dependency 'rotp', '~> 5.1'
diff --git a/spec/dummy/config/application.rb b/spec/dummy/config/application.rb
index 3c23b9d..a5e2c73 100644
--- a/spec/dummy/config/application.rb
+++ b/spec/dummy/config/application.rb
@@ -16,9 +16,9 @@
 
 module Dummy
   class Application < Rails::Application
-    config.load_defaults 5.0
-    unless ENV['BUNDLE_GEMFILE'].include?('mongodb')
-      Rails.application.config.active_record.sqlite3.represent_boolean_as_integer = true
-    end
+    # config.load_defaults 5.0
+    # unless ENV['BUNDLE_GEMFILE'].include?('mongodb')
+    #   Rails.application.config.active_record.sqlite3.represent_boolean_as_integer = true
+    # end
   end
 end
diff --git a/spec/dummy/config/environments/test.rb b/spec/dummy/config/environments/test.rb
index 9a24535..c9ecc12 100644
--- a/spec/dummy/config/environments/test.rb
+++ b/spec/dummy/config/environments/test.rb
@@ -13,10 +13,10 @@
   config.eager_load = true
 
   # Configure public file server for tests with Cache-Control for performance
-  config.public_file_server.enabled = true
-  config.public_file_server.headers = {
-    'Cache-Control' => "public, max-age=#{1.hour.to_i}"
-  }
+  # config.public_file_server.enabled = true
+  # config.public_file_server.headers = {
+  #   'Cache-Control' => "public, max-age=#{1.hour.to_i}"
+  # }
 
   # Show full error reports and disable caching
   config.consider_all_requests_local       = true
diff --git a/spec/dummy/config/initializers/devise.rb b/spec/dummy/config/initializers/devise.rb
index 0bc3442..0ab9793 100644
--- a/spec/dummy/config/initializers/devise.rb
+++ b/spec/dummy/config/initializers/devise.rb
@@ -8,7 +8,7 @@
   # confirmation, reset password and unlock tokens in the database.
   # Devise will use the `secret_key_base` as its `secret_key`
   # by default. You can change it below and use your own secret key.
-  # config.secret_key = '4e16edbe729fb51c9803b5397d7ea7827a6d8e6cd8a7fe8b09810652b9458afb623a14850fafdeee853815c09b140d3552eac721f571d8673f0e1be6c4707567'
+  config.secret_key = '4e16edbe729fb51c9803b5397d7ea7827a6d8e6cd8a7fe8b09810652b9458afb623a14850fafdeee853815c09b140d3552eac721f571d8673f0e1be6c4707567'
 
   # ==> Controller configuration
   # Configure the parent class to the devise controllers.