diff --git a/.travis.yml b/.travis.yml
index 4bbe45a7..485a1ebf 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -6,7 +6,7 @@ gemfile:
   - gemfiles/ruby_1.9.3_rails_3.2.gemfile
 rvm:
   - "1.9.3"
-  - "2.2.2"
+  - "2.6.3"
   - ruby-head
 matrix:
   allow_failures:
@@ -18,7 +18,7 @@ matrix:
       gemfile: gemfiles/rails_5_devise_4.gemfile
     - rvm: 1.9.3
       gemfile: gemfiles/rails_4_devise_3.gemfile
-    - rvm: 2.2.2
+    - rvm: 2.6.3
       gemfile: gemfiles/ruby_1.9.3_rails_3.2.gemfile
     - rvm: ruby-head
       gemfile: gemfiles/rails_4_devise_3.gemfile
diff --git a/README.md b/README.md
index 842c4e48..3185fb39 100644
--- a/README.md
+++ b/README.md
@@ -4,8 +4,7 @@ Simple Token Authentication
 [![Gem Version](https://badge.fury.io/rb/simple_token_authentication.svg)](http://badge.fury.io/rb/simple_token_authentication)
 [![Build Status](https://travis-ci.org/gonzalo-bulnes/simple_token_authentication.svg?branch=master)](https://travis-ci.org/gonzalo-bulnes/simple_token_authentication)
 [![Code Climate](https://codeclimate.com/github/gonzalo-bulnes/simple_token_authentication.svg)](https://codeclimate.com/github/gonzalo-bulnes/simple_token_authentication)
-[![Dependency Status](https://gemnasium.com/gonzalo-bulnes/simple_token_authentication.svg)](https://gemnasium.com/gonzalo-bulnes/simple_token_authentication)
-[![security](https://hakiri.io/github/gonzalo-bulnes/simple_token_authentication/master.svg)](https://hakiri.io/github/gonzalo-bulnes/simple_token_authentication/master)
+[![Security](https://hakiri.io/github/gonzalo-bulnes/simple_token_authentication/master.svg)](https://hakiri.io/github/gonzalo-bulnes/simple_token_authentication/master)
 [![Inline docs](http://inch-ci.org/github/gonzalo-bulnes/simple_token_authentication.svg?branch=master)](http://inch-ci.org/github/gonzalo-bulnes/simple_token_authentication)
 
 Token authentication support has been removed from [Devise][devise] for security reasons. In [this gist][original-gist], Devise's [José Valim][josevalim] explains how token authentication should be performed in order to remain safe.
diff --git a/lib/simple_token_authentication/adapters/mongoid_adapter.rb b/lib/simple_token_authentication/adapters/mongoid_adapter.rb
index 1d7ef6ea..0d2599b2 100644
--- a/lib/simple_token_authentication/adapters/mongoid_adapter.rb
+++ b/lib/simple_token_authentication/adapters/mongoid_adapter.rb
@@ -1,13 +1,20 @@
-require 'mongoid'
-require 'simple_token_authentication/adapter'
+if Module.const_defined?('ActiveModel') &&
+  ActiveModel.const_defined?('Serializers') &&
+  ActiveModel::Serializers.const_defined?('Xml')
+  # As far as I know Mongoid doesn't support Rails 6
+  # Please let me know if this isn't true when you read it!
 
-module SimpleTokenAuthentication
-  module Adapters
-    class MongoidAdapter
-      extend SimpleTokenAuthentication::Adapter
+  require 'mongoid'
+  require 'simple_token_authentication/adapter'
 
-      def self.base_class
-        ::Mongoid::Document
+  module SimpleTokenAuthentication
+    module Adapters
+      class MongoidAdapter
+        extend SimpleTokenAuthentication::Adapter
+
+        def self.base_class
+          ::Mongoid::Document
+        end
       end
     end
   end
diff --git a/spec/lib/simple_token_authentication/adapters/mongoid_adapter_spec.rb b/spec/lib/simple_token_authentication/adapters/mongoid_adapter_spec.rb
index 35c1d48c..0d9c299c 100644
--- a/spec/lib/simple_token_authentication/adapters/mongoid_adapter_spec.rb
+++ b/spec/lib/simple_token_authentication/adapters/mongoid_adapter_spec.rb
@@ -1,21 +1,28 @@
-require 'spec_helper'
-require 'simple_token_authentication/adapters/mongoid_adapter'
+if Module.const_defined?('ActiveModel') &&
+  ActiveModel.const_defined?('Serializers') &&
+  ActiveModel::Serializers.const_defined?('Xml')
+  # As far as I know Mongoid doesn't support Rails 6
+  # Please let me know if this isn't true when you read it!
 
-describe 'SimpleTokenAuthentication::Adapters::MongoidAdapter' do
+  require 'spec_helper'
+  require 'simple_token_authentication/adapters/mongoid_adapter'
 
-  before(:each) do
-    stub_const('Mongoid', Module.new)
-    stub_const('Mongoid::Document', double())
+  describe 'SimpleTokenAuthentication::Adapters::MongoidAdapter' do
 
-    @subject = SimpleTokenAuthentication::Adapters::MongoidAdapter
-  end
+    before(:each) do
+      stub_const('Mongoid', Module.new)
+      stub_const('Mongoid::Document', double())
+
+      @subject = SimpleTokenAuthentication::Adapters::MongoidAdapter
+    end
 
-  it_behaves_like 'an adapter'
+    it_behaves_like 'an adapter'
 
-  describe '.base_class' do
+    describe '.base_class' do
 
-    it 'is Mongoid::Document', private: true do
-      expect(@subject.base_class).to eq Mongoid::Document
+      it 'is Mongoid::Document', private: true do
+        expect(@subject.base_class).to eq Mongoid::Document
+      end
     end
   end
 end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index aa31a447..5518ab57 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -3,7 +3,6 @@
 
 require 'action_controller'
 require 'active_record'
-require 'mongoid'
 require 'active_support'
 
 require 'simple_token_authentication'