diff --git a/DependencyInjection/ColinFreiBitFieldTypeExtension.php b/DependencyInjection/ColinFreiBitFieldTypeExtension.php
deleted file mode 100644
index b22d5a3..0000000
--- a/DependencyInjection/ColinFreiBitFieldTypeExtension.php
+++ /dev/null
@@ -1,20 +0,0 @@
-<?php
-
-namespace ColinFrei\BitFieldTypeBundle\DependencyInjection;
-
-use Symfony\Component\DependencyInjection\ContainerBuilder;
-use Symfony\Component\Config\FileLocator;
-use Symfony\Component\HttpKernel\DependencyInjection\Extension;
-use Symfony\Component\DependencyInjection\Loader;
-
-class ColinFreiBitFieldTypeExtension extends Extension
-{
-    /**
-     * {@inheritDoc}
-     */
-    public function load(array $configs, ContainerBuilder $container)
-    {
-        $loader = new Loader\XmlFileLoader($container, new FileLocator(__DIR__.'/../Resources/config'));
-        $loader->load('services.xml');
-    }
-}
diff --git a/Form/Type/BitfieldType.php b/Form/Type/BitfieldType.php
index f440293..751786c 100644
--- a/Form/Type/BitfieldType.php
+++ b/Form/Type/BitfieldType.php
@@ -5,31 +5,36 @@
 use Symfony\Component\Form\AbstractType;
 use Symfony\Component\Form\FormBuilderInterface;
 use Symfony\Component\Form\Extension\Core\Type\ChoiceType;
+use Symfony\Component\OptionsResolver\OptionsResolver;
 
 use ColinFrei\BitFieldTypeBundle\Form\DataTransformer\BitfieldToArrayTransformer;
 
 class BitfieldType extends AbstractType
 {
-    public function getDefaultOptions(array $options)
+    /**
+     * {@inheritDoc}
+     */
+    public function configureOptions(OptionsResolver $resolver)
     {
-        return array(
+        $resolver->setDefaults(array(
             'expanded' => true,
             'multiple' => true,
-        );
+        ));
     }
 
+    /**
+     * {@inheritDoc}
+     */
     public function buildForm(FormBuilderInterface $builder, array $options)
     {
         $builder->addModelTransformer(new BitfieldToArrayTransformer());
     }
 
+    /**
+     * {@inheritDoc}
+     */
     public function getParent()
     {
-        return new ChoiceType();
+        return ChoiceType::class;
     }
-
-    public function getName()
-    {
-        return 'bitfield';
-    }
-}
\ No newline at end of file
+}
diff --git a/README.md b/README.md
index ff04051..fe92241 100644
--- a/README.md
+++ b/README.md
@@ -19,12 +19,15 @@ Register the bundle in your app/AppKernel.php file, by adding this line in the `
 
 ## Usage
 
-Use the type `bitfield` when adding fields to the form, and pass in an array of options, like the type line in this example from the [Symfony documentation](http://symfony.com/doc/current/book/forms.html#building-the-form):
+Use the `BitfieldType` class when adding fields to the form, and pass in an array of options, like the type line in this example from the [Symfony documentation](http://symfony.com/doc/current/book/forms.html#building-the-form):
 
+    use ColinFrei\BitFieldTypeBundle\Form\Type\BitfieldType;
+    
     $form = $this->createFormBuilder($task)
         ->add('task', 'text')
         ->add('dueDate', 'date')
-        ->add('type', 'bitfield', array(
-            'choices' => array('1' => 'Annoying', '2' => 'Fun', '4' => 'Cool', '8' => 'Takes a while')
+        ->add('type', BitfieldType::class, array(
+            'choices' => array('Annoying' => '1', 'Fun' => '2', 'Cool' => '4', 'Takes a while' => '8'),
+            'choices_as_values' => true
         )
         ->getForm();
\ No newline at end of file
diff --git a/Resources/config/services.xml b/Resources/config/services.xml
deleted file mode 100644
index fa33147..0000000
--- a/Resources/config/services.xml
+++ /dev/null
@@ -1,13 +0,0 @@
-<?xml version="1.0" ?>
-
-<container xmlns="http://symfony.com/schema/dic/services"
-    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">
-
-    <services>
-        <service id="colinfrei.bitfield_type.form.bitfield_type"
-                 class="ColinFrei\BitFieldTypeBundle\Form\Type\BitfieldType">
-            <tag name="form.type" alias="bitfield" />
-        </service>
-    </services>
-</container>
diff --git a/composer.json b/composer.json
index 9a727b3..3a541aa 100644
--- a/composer.json
+++ b/composer.json
@@ -3,7 +3,7 @@
     "description": "Adds a bitfield type to use in Symfony Forms",
     "license": "MIT",
     "require": {
-        "symfony/symfony": "~2.6"
+        "symfony/symfony": "~2.7"
     },
     "authors": [
         {