diff --git a/service_container.rst b/service_container.rst
index 12e0705ae32..11ea370ee29 100644
--- a/service_container.rst
+++ b/service_container.rst
@@ -10,15 +10,10 @@ send emails while another object might help you save things to the database.
 Almost *everything* that your app "does" is actually done by one of these objects.
 And each time you install a new bundle, you get access to even more!
 
-In Symfony, these useful objects are called **services** and each service lives inside
-a very special object called the **service container**. If you have the service container,
-then you can fetch a service by using that service's id::
-
-    $logger = $container->get('logger');
-    $entityManager = $container->get('doctrine.orm.entity_manager');
-
-The container allows you to centralize the way objects are constructed. It makes
-your life easier, promotes a strong architecture and is super fast!
+In Symfony, these useful objects are called **services** and each service lives
+inside a very special object called the **service container**. The container
+allows you to centralize the way objects are constructed. It makes your life
+easier, promotes a strong architecture and is super fast!
 
 Fetching and using Services
 ---------------------------
@@ -36,7 +31,7 @@ service's class or interface name. Want to :doc:`log </logging>` something? No p
     /**
      * @Route("/products")
      */
-    public function listAction(LoggerInterface $logger)
+    public function list(LoggerInterface $logger)
     {
         $logger->info('Look! I just used a service');
 
@@ -83,7 +78,7 @@ You can also use the unique "Service ID" to access a service directly::
         /**
          * @Route("/products")
          */
-        public function listAction()
+        public function list()
         {
             $logger = $this->container->get('logger');
             $logger->info('Look! I just used a service');
@@ -146,7 +141,7 @@ inside your controller::
 
     use App\Service\MessageGenerator;
 
-    public function newAction(MessageGenerator $messageGenerator)
+    public function new(MessageGenerator $messageGenerator)
     {
         // thanks to the type-hint, the container will instantiate a
         // new MessageGenerator and pass it to you!
@@ -167,9 +162,7 @@ each time you ask for it.
 
 .. sidebar:: Automatic Service Loading in services.yaml
 
-    The documentation assumes you're using
-    `Symfony Standard Edition (version 3.3) services.yaml`_ configuration. The most
-    important part is this:
+    The documentation assumes you're using the following service configuration:
 
     .. configuration-block::
 
@@ -185,10 +178,10 @@ each time you ask for it.
 
                 # makes classes in src/ available to be used as services
                 App\:
-                    resource: '../../src/*'
+                    resource: '../src/*'
                     # you can exclude directories or files
                     # but if a service is unused, it's removed anyway
-                    exclude: '../../src/{Entity,Repository}'
+                    exclude: '../src/{Entity,Repository}'
 
         .. code-block:: xml
 
@@ -204,7 +197,7 @@ each time you ask for it.
                     <defaults autowire="true" autoconfigure="true" public="false" />
 
                     <!-- Load services from whatever directories you want (you can update this!) -->
-                    <prototype namespace="App\" resource="../../src/*" exclude="../../src/{Entity,Repository}" />
+                    <prototype namespace="App\" resource="../src/*" exclude="../src/{Entity,Repository}" />
                 </services>
             </container>
 
@@ -223,7 +216,7 @@ each time you ask for it.
             ;
 
             // $this is a reference to the current loader
-            $this->registerClasses($definition, 'App\\', '../../src/*', '../../src/{Entity,Repository}');
+            $this->registerClasses($definition, 'App\\', '../src/*', '../src/{Entity,Repository}');
 
     .. tip::
 
@@ -237,15 +230,16 @@ each time you ask for it.
     If you'd prefer to manually wire your service, that's totally possible: see
     :ref:`services-explicitly-configure-wire-services`.
 
-You can also fetch a service directly from the container via its "id", which will
-be its class name in this case::
+If the :ref:`service is public <container-public>`, you can also fetch it
+directly from the container via its "id". However, this practice is discouraged
+and you should instead inject services via constructors::
 
     use App\Service\MessageGenerator;
 
     // accessing services like this only works if you extend Controller
     class ProductController extends Controller
     {
-        public function newAction()
+        public function new()
         {
             // only works if your service is public
             $messageGenerator = $this->get(MessageGenerator::class);
@@ -256,8 +250,6 @@ be its class name in this case::
         }
     }
 
-However, this only works if you make your service :ref:`public <container-public>`.
-
 .. _services-constructor-injection:
 
 Injecting Services/Config into a Service
@@ -368,7 +360,7 @@ you can use the service immediately::
 
     use App\Updates\SiteUpdateManager;
 
-    public function newAction(SiteUpdateManager $siteUpdateManager)
+    public function new(SiteUpdateManager $siteUpdateManager)
     {
         // ...
 
@@ -438,8 +430,8 @@ pass here. No problem! In your configuration, you can explicitly set this argume
 
             # same as before
             App\:
-                resource: '../../src/*'
-                exclude: '../../src/{Entity,Repository}'
+                resource: '../src/*'
+                exclude: '../src/{Entity,Repository}'
 
             # explicitly configure the service
             App\Updates\SiteUpdateManager:
@@ -459,7 +451,7 @@ pass here. No problem! In your configuration, you can explicitly set this argume
                 <!-- ... -->
 
                 <!-- Same as before -->
-                <prototype namespace="App\" resource="../../src/*" exclude="../../src/{Entity,Repository}" />
+                <prototype namespace="App\" resource="../src/*" exclude="../src/{Entity,Repository}" />
 
                 <!-- Explicitly configure the service -->
                 <service id="App\Updates\SiteUpdateManager">
@@ -483,7 +475,7 @@ pass here. No problem! In your configuration, you can explicitly set this argume
             ->setPublic(false)
         ;
 
-        $this->registerClasses($definition, 'App\\', '../../src/*', '../../src/{Entity,Repository}');
+        $this->registerClasses($definition, 'App\\', '../src/*', '../src/{Entity,Repository}');
 
         // Explicitly configure the service
         $container->getDefinition(SiteUpdateManager::class)
@@ -553,9 +545,9 @@ and reference it with the ``%parameter_name%`` syntax:
             // ...
             ->setArgument('$adminEmail', '%admin_email%');
 
-Actually, once you define a parameter, it can be referenced via the ``%parameter_name%``
-syntax in *any* other service configuration file - like ``config.yml``. Many parameters
-are defined in a :ref:`parameters.yml file <config-parameters-yml>`.
+Actually, once you define a parameter, it can be referenced via the
+``%parameter_name%`` syntax in *any* other configuration file. Many parameters
+are defined in the ``config/services.yaml`` file.
 
 You can then fetch the parameter in the service::
 
@@ -573,11 +565,11 @@ You can then fetch the parameter in the service::
 
 You can also fetch parameters directly from the container::
 
-    public function newAction()
+    public function new()
     {
         // ...
 
-        // this ONLY works if you extend Controller
+        // this ONLY works if you extend the base Controller
         $adminEmail = $this->container->getParameter('admin_email');
 
         // or a shorter way!
@@ -741,7 +733,7 @@ as a service, and :doc:`tag </service_container/tags>` it with ``twig.extension`
             ->addTag('twig.extension');
 
 But, with ``autoconfigure: true``, you don't need the tag. In fact, if you're using
-the :ref:`Symfony Standard Edition services.yaml config <service-container-services-load-example>`,
+the :ref:`default services.yaml config <service-container-services-load-example>`,
 you don't need to do *anything*: the service will be automatically loaded. Then,
 ``autoconfigure`` will add the ``twig.extension`` tag *for* you, because your class
 implements ``Twig_ExtensionInterface``. And thanks to ``autowire``, you can even add
@@ -789,7 +781,7 @@ from the container::
 
     use App\Service\MessageGenerator;
 
-    public function newAction(MessageGenerator $messageGenerator)
+    public function new(MessageGenerator $messageGenerator)
     {
         // type-hinting it as an argument DOES work
 
@@ -797,7 +789,7 @@ from the container::
         $this->container->get(MessageGenerator::class);
     }
 
-Usually, this is ok: there are better ways to access a service. But, if you *do*
+Usually, this is OK: there are better ways to access a service. But, if you *do*
 need to make your service public, just override this setting:
 
 .. configuration-block::
@@ -848,13 +840,13 @@ key. For example, the default Symfony configuration contains this:
             # the namespace prefix for classes (must end in \)
             App\:
                 # create services for all the classes found in this directory...
-                resource: '../../src/*'
+                resource: '../src/*'
                 # ...except for the classes located in these directories
-                exclude: '../../src/{Entity,Repository}'
+                exclude: '../src/{Entity,Repository}'
 
             # these were imported above, but we want to add some extra config
             App\Controller\:
-                resource: '../../src/Controller'
+                resource: '../src/Controller'
                 # apply some configuration to these services
                 public: true
                 tags: ['controller.service_arguments']
@@ -871,9 +863,9 @@ key. For example, the default Symfony configuration contains this:
             <services>
                 <!-- ... -->
 
-                <prototype namespace="App\" resource="../../src/*" exclude="../../src/{Entity,Repository}" />
+                <prototype namespace="App\" resource="../src/*" exclude="../src/{Entity,Repository}" />
 
-                <prototype namespace="App\Controller\" resource="../../src/Controller" public="true">
+                <prototype namespace="App\Controller\" resource="../src/Controller" public="true">
                     <tag name="controller.service_arguments" />
                 </prototype>
             </services>
@@ -893,7 +885,7 @@ key. For example, the default Symfony configuration contains this:
             ->setPublic(false)
         ;
 
-        $this->registerClasses($definition, 'App\\', '../../src/*', '../../src/{Entity,Repository}');
+        $this->registerClasses($definition, 'App\\', '../src/*', '../src/{Entity,Repository}');
 
         // Changes default config
         $definition
@@ -902,7 +894,7 @@ key. For example, the default Symfony configuration contains this:
         ;
 
         // $this is a reference to the current loader
-        $this->registerClasses($definition, 'App\\Controller\\', '../../src/Controller/*');
+        $this->registerClasses($definition, 'App\\Controller\\', '../src/Controller/*');
 
 .. tip::
 
diff --git a/service_container/3.3-di-changes.rst b/service_container/3.3-di-changes.rst
index ba4445ad42c..2cc1afec728 100644
--- a/service_container/3.3-di-changes.rst
+++ b/service_container/3.3-di-changes.rst
@@ -49,15 +49,15 @@ Symfony Standard Edition:
             # makes classes in src/ available to be used as services
             # this creates a service per class whose id is the fully-qualified class name
             App\:
-                resource: '../../src/*'
+                resource: '../src/*'
                 # you can exclude directories or files
                 # but if a service is unused, it's removed anyway
-                exclude: '../../src/{Entity,Repository}'
+                exclude: '../src/{Entity,Repository}'
 
             # controllers are imported separately to make sure they're public
             # and have a tag that allows actions to type-hint services
             App\Controller\:
-                resource: '../../src/Controller'
+                resource: '../src/Controller'
                 tags: ['controller.service_arguments']
 
             # add more services, or override services that need manual wiring
@@ -77,9 +77,9 @@ Symfony Standard Edition:
             <services>
                 <defaults autowire="true" autoconfigure="true" public="false" />
 
-                <prototype namespace="App\" resource="../../src/*" exclude="../../src/{Entity,Repository}" />
+                <prototype namespace="App\" resource="../src/*" exclude="../src/{Entity,Repository}" />
 
-                <prototype namespace="App\Controller\" resource="../../src/Controller">
+                <prototype namespace="App\Controller\" resource="../src/Controller">
                     <tag name="controller.service_arguments" />
                 </prototype>
 
@@ -101,7 +101,7 @@ Symfony Standard Edition:
             ->setPublic(false)
         ;
 
-        $this->registerClasses($definition, 'App\\', '../../src/*', '../../src/{Entity,Repository}');
+        $this->registerClasses($definition, 'App\\', '../src/*', '../src/{Entity,Repository}');
 
         // Changes default config
         $definition
@@ -109,7 +109,7 @@ Symfony Standard Edition:
         ;
 
         // $this is a reference to the current loader
-        $this->registerClasses($definition, 'App\\Controller\\', '../../src/Controller/*');
+        $this->registerClasses($definition, 'App\\Controller\\', '../src/Controller/*');
 
         // add more services, or override services that need manual wiring
 
@@ -139,10 +139,10 @@ thanks to the following config:
             # makes classes in src/ available to be used as services
             # this creates a service per class whose id is the fully-qualified class name
             App\:
-                resource: '../../src/*'
+                resource: '../src/*'
                 # you can exclude directories or files
                 # but if a service is unused, it's removed anyway
-                exclude: '../../src/{Entity,Repository}'
+                exclude: '../src/{Entity,Repository}'
 
     .. code-block:: xml
 
@@ -156,7 +156,7 @@ thanks to the following config:
             <services>
                 <!-- ... -->
 
-                <prototype namespace="App\" resource="../../src/*" exclude="../../src/{Entity,Repository}" />
+                <prototype namespace="App\" resource="../src/*" exclude="../src/{Entity,Repository}" />
             </services>
         </container>
 
@@ -174,7 +174,7 @@ thanks to the following config:
             ->setPublic(false)
         ;
 
-        $this->registerClasses($definition, 'App\\', '../../src/*', '../../src/{Entity,Repository}');
+        $this->registerClasses($definition, 'App\\', '../src/*', '../src/{Entity,Repository}');
 
 This means that every class in ``src/`` is *available* to be used as a
 service. And thanks to the ``_defaults`` section at the top of the file, all of
@@ -345,7 +345,7 @@ The third big change is that, in a new Symfony 3.3 project, your controllers are
             # controllers are imported separately to make sure they're public
             # and have a tag that allows actions to type-hint services
             App\Controller\:
-                resource: '../../src/Controller'
+                resource: '../src/Controller'
                 tags: ['controller.service_arguments']
 
     .. code-block:: xml
@@ -360,7 +360,7 @@ The third big change is that, in a new Symfony 3.3 project, your controllers are
             <services>
                 <!-- ... -->
 
-                <prototype namespace="App\Controller\" resource="../../src/Controller">
+                <prototype namespace="App\Controller\" resource="../src/Controller">
                     <tag name="controller.service_arguments" />
                 </prototype>
             </services>
@@ -372,7 +372,7 @@ The third big change is that, in a new Symfony 3.3 project, your controllers are
 
         // ...
 
-        $this->registerClasses($definition, 'App\\Controller\\', '../../src/Controller/*');
+        $this->registerClasses($definition, 'App\\Controller\\', '../src/Controller/*');
 
 But, you might not even notice this. First, your controllers *can* still extend
 the same base ``Controller`` class or a new :ref:`AbstractController <controller-abstract-versus-controller>`.
@@ -720,11 +720,11 @@ You're now ready to automatically register all services in ``src/``
             # ...
 
     +     App\:
-    +         resource: '../../src/*'
-    +         exclude: '../../src/{Entity,Repository}'
+    +         resource: '../src/*'
+    +         exclude: '../src/{Entity,Repository}'
     +
     +     App\Controller\:
-    +         resource: '../../src/Controller'
+    +         resource: '../src/Controller'
     +         tags: ['controller.service_arguments']
 
         # ...
@@ -809,11 +809,11 @@ can be autowired. The final configuration looks like this:
             public: false
 
         App\:
-            resource: '../../src/*'
-            exclude: '../../src/{Entity,Repository}'
+            resource: '../src/*'
+            exclude: '../src/{Entity,Repository}'
 
         App\Controller\:
-            resource: '../../src/Controller'
+            resource: '../src/Controller'
             tags: ['controller.service_arguments']
 
         App\Service\GitHubNotifier:
diff --git a/service_container/alias_private.rst b/service_container/alias_private.rst
index b6bd077fa30..b57099960f9 100644
--- a/service_container/alias_private.rst
+++ b/service_container/alias_private.rst
@@ -32,6 +32,7 @@ You can also control the ``public`` option on a service-by-service basis:
 
     .. code-block:: yaml
 
+        # config/services.yaml
         services:
             # ...
 
@@ -40,6 +41,7 @@ You can also control the ``public`` option on a service-by-service basis:
 
     .. code-block:: xml
 
+        <!-- config/services.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -52,6 +54,7 @@ You can also control the ``public`` option on a service-by-service basis:
 
     .. code-block:: php
 
+        // config/services.php
         use App\Service\Foo;
 
         $container->register(Foo::class)
@@ -80,11 +83,6 @@ to access it directly from your code.
 However, if a service has been marked as private, you can still alias it
 (see below) to access this service (via the alias).
 
-.. note::
-
-    Services are by default public, but it's considered a good practice to mark
-    as many services private as possible.
-
 .. _services-alias:
 
 Aliasing
@@ -98,6 +96,7 @@ services.
 
     .. code-block:: yaml
 
+        # config/services.yaml
         services:
             # ...
             App\Mail\PhpMailer:
@@ -109,6 +108,7 @@ services.
 
     .. code-block:: xml
 
+        <!-- config/services.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -124,6 +124,7 @@ services.
 
     .. code-block:: php
 
+        // config/services.php
         use App\Mail\PhpMailer;
 
         $container->register(PhpMailer::class)
@@ -142,6 +143,7 @@ This means that when using the container directly, you can access the
 
     .. code-block:: yaml
 
+        # config/services.yaml
         services:
             # ...
             app.mailer: '@App\Mail\PhpMailer'
@@ -156,11 +158,13 @@ or you decided not to maintain it anymore), you can deprecate its definition:
 
     .. code-block:: yaml
 
-       App\Service\OldService:
-           deprecated: The "%service_id%" service is deprecated since 2.8 and will be removed in 3.0.
+        # config/services.yaml
+        App\Service\OldService:
+            deprecated: The "%service_id%" service is deprecated since 2.8 and will be removed in 3.0.
 
     .. code-block:: xml
 
+        <!-- config/services.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-Instance"
@@ -175,6 +179,7 @@ or you decided not to maintain it anymore), you can deprecate its definition:
 
     .. code-block:: php
 
+        // config/services.php
         use App\Service\OldService;
 
         $container
diff --git a/service_container/autowiring.rst b/service_container/autowiring.rst
index eafb2682898..8061e54bdad 100644
--- a/service_container/autowiring.rst
+++ b/service_container/autowiring.rst
@@ -69,6 +69,7 @@ both services. Also, to keep things simple, configure ``TwitterClient`` to be a
 
     .. code-block:: yaml
 
+        # config/services.yaml
         services:
             _defaults:
                 autowire: true
@@ -87,6 +88,7 @@ both services. Also, to keep things simple, configure ``TwitterClient`` to be a
 
     .. code-block:: xml
 
+        <!-- config/services.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -104,6 +106,7 @@ both services. Also, to keep things simple, configure ``TwitterClient`` to be a
 
     .. code-block:: php
 
+        // config/services.php
         use App\Service\TwitterClient;
         use App\Util\Rot13Transformer;
 
@@ -130,7 +133,7 @@ Now, you can use the ``TwitterClient`` service immediately in a controller::
         /**
          * @Route("/tweet")
          */
-        public function tweetAction()
+        public function tweet()
         {
             // fetch $user, $key, $status from the POST'ed data
 
@@ -203,7 +206,7 @@ which allows us to autowire this type automatically.
 This can also be accomplished using an :ref:`alias <services-alias>`. Suppose that
 for some reason, the id of the service was instead ``app.rot13.transformer``. In
 this case, any arguments type-hinted with the class name (``App\Util\Rot13Transformer``)
-can no longer be autowired (actually, it :ref:`will work now, but not in Symfony 4.0 <autowiring-single-matching-service>`).
+can no longer be autowired.
 
 No problem! To fix this, you can *create* a service whose id matches the class by
 adding a service alias:
@@ -212,6 +215,7 @@ adding a service alias:
 
     .. code-block:: yaml
 
+        # config/services.yaml
         services:
             # ...
 
@@ -227,6 +231,7 @@ adding a service alias:
 
     .. code-block:: xml
 
+        <!-- config/services.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -242,6 +247,7 @@ adding a service alias:
 
     .. code-block:: php
 
+        // config/services.php
         use App\Util\Rot13Transformer;
 
         // ...
@@ -301,8 +307,7 @@ Now that you have an interface, you should use this as your type-hint::
 
 But now, the type-hint (``App\Util\TransformerInterface``) no longer matches
 the id of the service (``App\Util\Rot13Transformer``). This means that the
-argument can no longer be autowired (actually, it
-:ref:`will work now, but not in Symfony 4.0 <autowiring-single-matching-service>`).
+argument can no longer be autowired.
 
 To fix that, add an :ref:`alias <service-autowiring-alias>`:
 
@@ -310,6 +315,7 @@ To fix that, add an :ref:`alias <service-autowiring-alias>`:
 
     .. code-block:: yaml
 
+        # config/services.yaml
         services:
             # ...
 
@@ -321,6 +327,7 @@ To fix that, add an :ref:`alias <service-autowiring-alias>`:
 
     .. code-block:: xml
 
+        <!-- config/services.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -336,6 +343,7 @@ To fix that, add an :ref:`alias <service-autowiring-alias>`:
 
     .. code-block:: php
 
+        // config/services.php
         use App\Util\Rot13Transformer;
         use App\Util\TransformerInterface;
 
@@ -375,6 +383,7 @@ that alias:
 
     .. code-block:: yaml
 
+        # config/services.yaml
         services:
             # ...
 
@@ -396,6 +405,7 @@ that alias:
 
     .. code-block:: xml
 
+        <!-- config/services.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -416,6 +426,7 @@ that alias:
 
     .. code-block:: php
 
+        // config/services.php
         use App\Util\Rot13Transformer;
         use App\Util\UppercaseTransformer;
         use App\Util\TransformerInterface;
diff --git a/service_container/compiler_passes.rst b/service_container/compiler_passes.rst
index c8a55ece04f..4d8abfea7ca 100644
--- a/service_container/compiler_passes.rst
+++ b/service_container/compiler_passes.rst
@@ -2,26 +2,85 @@
    single: DependencyInjection; Compiler passes
    single: Service Container; Compiler passes
 
-How to Work with Compiler Passes in Bundles
-===========================================
+How to Work with Compiler Passes
+================================
 
 Compiler passes give you an opportunity to manipulate other service
 definitions that have been registered with the service container. You
 can read about how to create them in the components section
 ":ref:`components-di-compiler-pass`".
 
-When using :ref:`separate compiler passes <components-di-separate-compiler-passes>`,
-you need to register them in the ``build()`` method of the bundle class (this
-is not needed when implementing the ``process()`` method in the extension)::
+Compiler passes are registered in the ``build()`` method of the application kernel::
 
-    // src/AppBundle.php
-    namespace AppBundle;
+    // src/Kernel.php
+    namespace App;
+
+    use App\DependencyInjection\Compiler\CustomPass;
+    use Symfony\Bundle\FrameworkBundle\Kernel\MicroKernelTrait;
+    use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
+    use Symfony\Component\DependencyInjection\ContainerBuilder;
+    use Symfony\Component\HttpKernel\Kernel as BaseKernel;
+
+    class Kernel extends BaseKernel implements CompilerPassInterface
+    {
+        use MicroKernelTrait;
+
+        // ...
+
+        protected function build(ContainerBuilder $container): void
+        {
+            $container->addCompilerPass(new CustomPass());
+        }
+    }
+
+One of the most common use-cases of compiler passes is to work with :doc:`tagged
+services </service_container/tags>`. In those cases, instead of creating a
+compiler pass, you can make the kernel implement
+:class:`Symfony\\Component\\DependencyInjection\\Compiler\\CompilerPassInterface`
+and process the services inside the ``process()`` method::
+
+    // src/Kernel.php
+    namespace App;
+
+    use Symfony\Bundle\FrameworkBundle\Kernel\MicroKernelTrait;
+    use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
+    use Symfony\Component\DependencyInjection\ContainerBuilder;
+    use Symfony\Component\HttpKernel\Kernel as BaseKernel;
+
+    class Kernel extends BaseKernel implements CompilerPassInterface
+    {
+        use MicroKernelTrait;
+
+        // ...
+
+        public function process(ContainerBuilder $container)
+        {
+            // in this method you can manipulate the service container:
+            // for example, changing some container service:
+            $container->getDefinition('app.some_private_service')->setPublic(true);
+
+            // or processing tagged services:
+            foreach ($container->findTaggedServiceIds('some_tag') as $id => $tags) {
+                // ...
+            }
+        }
+    }
+
+Working with Compiler Passes in Bundles
+---------------------------------------
+
+`Bundles </bundles>`_ can define compiler passes in the ``build()`` method of
+the main bundle class (this is not needed when implementing the ``process()``
+method in the extension)::
+
+    // src/MyBundle/MyBundle.php
+    namespace App\MyBundle;
 
     use Symfony\Component\HttpKernel\Bundle\Bundle;
     use Symfony\Component\DependencyInjection\ContainerBuilder;
     use App\DependencyInjection\Compiler\CustomPass;
 
-    class AppBundle extends Bundle
+    class MyBundle extends Bundle
     {
         public function build(ContainerBuilder $container)
         {
@@ -31,10 +90,8 @@ is not needed when implementing the ``process()`` method in the extension)::
         }
     }
 
-One of the most common use-cases of compiler passes is to work with tagged services
-(read more about tags in ":doc:`/service_container/tags`"). If you are using
-custom tags in a bundle then by convention, tag names consist of the name of
-the bundle (lowercase, underscores as separators), followed by a dot, and
-finally the "real" name. For example, if you want to introduce some sort of
-"transport" tag in your AcmeMailerBundle, you should call it
-``acme_mailer.transport``.
+If you are using custom service tags in a bundle then by convention, tag names
+consist of the name of the bundle (lowercase, underscores as separators),
+followed by a dot, and finally the "real" name. For example, if you want to
+introduce some sort of "transport" tag in your AcmeMailerBundle, you should call
+it ``acme_mailer.transport``.
diff --git a/service_container/configurators.rst b/service_container/configurators.rst
index 20ceaeed18c..7f2817e0a56 100644
--- a/service_container/configurators.rst
+++ b/service_container/configurators.rst
@@ -131,7 +131,7 @@ all the classes are already loaded as services. All you need to do is specify th
 
             # Registers all 4 classes as services, including App\Mail\EmailConfigurator
             App\:
-                resource: '../../src/*'
+                resource: '../src/*'
                 # ...
 
             # override the services to set the configurator
@@ -151,7 +151,7 @@ all the classes are already loaded as services. All you need to do is specify th
                 http://symfony.com/schema/dic/services/services-1.0.xsd">
 
             <services>
-                <prototype namespace="App\" resource="../../src/*" />
+                <prototype namespace="App\" resource="../src/*" />
 
                 <service id="App\Mail\NewsletterManager">
                     <configurator service="App\Mail\EmailConfigurator" method="configure" />
@@ -176,7 +176,7 @@ all the classes are already loaded as services. All you need to do is specify th
 
         $definition->setAutowired(true);
 
-        $this->registerClasses($definition, 'App\\', '../../src/*');
+        $this->registerClasses($definition, 'App\\', '../src/*');
 
         $container->getDefinition(NewsletterManager::class)
             ->setConfigurator(array(new Reference(EmailConfigurator::class), 'configure'));
diff --git a/service_container/expression_language.rst b/service_container/expression_language.rst
index c6878e413e9..cbab6c2ffde 100644
--- a/service_container/expression_language.rst
+++ b/service_container/expression_language.rst
@@ -78,12 +78,14 @@ via a ``container`` variable. Here's another example:
 
     .. code-block:: yaml
 
+        # config/services.yaml
         services:
             App\Mailer:
                 arguments: ["@=container.hasParameter('some_param') ? parameter('some_param') : 'default_value'"]
 
     .. code-block:: xml
 
+        <!-- config/services.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -99,6 +101,7 @@ via a ``container`` variable. Here's another example:
 
     .. code-block:: php
 
+        // config/services.php
         use App\Mailer;
         use Symfony\Component\ExpressionLanguage\Expression;
 
diff --git a/service_container/factories.rst b/service_container/factories.rst
index 21cf8875255..6f723ddf640 100644
--- a/service_container/factories.rst
+++ b/service_container/factories.rst
@@ -46,7 +46,6 @@ configure the service container to use the
     .. code-block:: xml
 
         <!-- config/services.xml -->
-
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -64,7 +63,6 @@ configure the service container to use the
     .. code-block:: php
 
         // config/services.php
-
         use App\Email\NewsletterManager;
         use App\NumberGenerator;
         use App\Email\NewsletterManagerStaticFactory;
@@ -94,7 +92,6 @@ Configuration of the service container then looks like this:
     .. code-block:: yaml
 
         # config/services.yaml
-
         services:
             # ...
 
@@ -107,7 +104,6 @@ Configuration of the service container then looks like this:
     .. code-block:: xml
 
         <!-- config/services.xml -->
-
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -129,7 +125,6 @@ Configuration of the service container then looks like this:
     .. code-block:: php
 
         // config/services.php
-
         use App\Email\NewsletterManager;
         use App\Email\NewsletterManagerFactory;
         // ...
@@ -151,9 +146,8 @@ Configuration of the service container then looks like this:
     .. code-block:: yaml
 
         # config/services.yaml
-
         app.newsletter_manager:
-            class: App\Email\NewsletterManager 
+            class: App\Email\NewsletterManager
             # new syntax
             factory: 'App\Email\NewsletterManagerFactory:createNewsletterManager'
             # old syntax
@@ -178,7 +172,6 @@ example takes the ``templating`` service as an argument:
     .. code-block:: yaml
 
         # config/services.yaml
-
         services:
             # ...
 
@@ -189,7 +182,6 @@ example takes the ``templating`` service as an argument:
     .. code-block:: xml
 
         <!-- config/services.xml -->
-
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -209,7 +201,6 @@ example takes the ``templating`` service as an argument:
     .. code-block:: php
 
         // config/services.php
-
         use App\Email\NewsletterManager;
         use App\Email\NewsletterManagerFactory;
         use Symfony\Component\DependencyInjection\Reference;
diff --git a/service_container/import.rst b/service_container/import.rst
index 76647d99c43..cc622ca4f7b 100644
--- a/service_container/import.rst
+++ b/service_container/import.rst
@@ -13,10 +13,8 @@ How to Import Configuration Files/Resources
     web service).
 
 The service container is built using a single configuration resource
-(``app/config/config.yml`` by default). All other service configuration
-(including the core Symfony and third-party bundle configuration) must
-be imported from inside this file in one way or another. This gives you absolute
-flexibility over the services in your application.
+(``config/services.yaml`` by default). This gives you absolute flexibility over
+the services in your application.
 
 External service configuration can be imported in two different ways. The first
 method, commonly used to import other resources, is via the ``imports``
@@ -40,7 +38,7 @@ decided to move some configuration to a new file:
 
     .. code-block:: yaml
 
-        # app/config/services/mailer.yml
+        # config/services/mailer.yaml
         parameters:
             # ... some parameters
 
@@ -49,7 +47,7 @@ decided to move some configuration to a new file:
 
     .. code-block:: xml
 
-        <!-- app/config/services/mailer.xml -->
+        <!-- config/services/mailer.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -67,7 +65,7 @@ decided to move some configuration to a new file:
 
     .. code-block:: php
 
-        // app/config/services/mailer.php
+        // config/services/mailer.php
 
         // ... some parameters
         // ... some services
@@ -80,7 +78,7 @@ To import this file, use the ``imports`` key from a file that *is* loaded:
 
         # config/services.yaml
         imports:
-            - { resource: services/mailer.yml }
+            - { resource: services/mailer.yaml }
 
     .. code-block:: xml
 
@@ -115,7 +113,7 @@ Importing Configuration via Container Extensions
 ------------------------------------------------
 
 Third-party bundle container configuration, including Symfony core services,
-are usually loaded using another method: a container extension.
+are usually loaded using another method: a :doc:`container extension </bundles/extension>`.
 
 Internally, each bundle defines its services in files like you've seen so far.
 However, these files aren't imported using the ``import`` directive. Instead, bundles
@@ -123,10 +121,6 @@ use a *dependency injection extension* to load the files automatically. As soon
 as you enable a bundle, its extension is called, which is able to load service
 configuration files.
 
-In fact, each configuration block in ``config.yml`` - e.g. ``framework`` or ``twig``-
-is passed to the extension for that bundle - e.g. ``FrameworkBundle`` or ``TwigBundle`` -
+In fact, each configuration file in ``config/packages/`` is passed to the
+extension of its related  bundle - e.g. ``FrameworkBundle`` or ``TwigBundle`` -
 and used to configure those services further.
-
-If you want to use dependency injection extensions in your own shared
-bundles and provide user friendly configuration, take a look at the
-:doc:`/bundles/extension` article.
diff --git a/service_container/injection_types.rst b/service_container/injection_types.rst
index e5c7fe78dbf..60478f66a5f 100644
--- a/service_container/injection_types.rst
+++ b/service_container/injection_types.rst
@@ -41,7 +41,8 @@ service container configuration:
 
     .. code-block:: yaml
 
-       services:
+        # config/services.yaml
+        services:
             # ...
 
             App\Mail\NewsletterManager:
@@ -49,6 +50,7 @@ service container configuration:
 
     .. code-block:: xml
 
+        <!-- config/services.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -66,6 +68,7 @@ service container configuration:
 
     .. code-block:: php
 
+        // config/services.php
         use App\Mail\NewsletterManager;
         use Symfony\Component\DependencyInjection\Reference;
 
@@ -120,6 +123,7 @@ that accepts the dependency::
 
     .. code-block:: yaml
 
+        # config/services.yaml
        services:
             # ...
 
@@ -130,6 +134,7 @@ that accepts the dependency::
 
     .. code-block:: xml
 
+        <!-- config/services.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -149,6 +154,7 @@ that accepts the dependency::
 
     .. code-block:: php
 
+        // config/services.php
         use App\Mail\NewsletterManager;
         use Symfony\Component\DependencyInjection\Reference;
 
@@ -192,6 +198,7 @@ Another possibility is just setting public fields of the class directly::
 
     .. code-block:: yaml
 
+        # config/services.yaml
        services:
             # ...
 
@@ -202,6 +209,7 @@ Another possibility is just setting public fields of the class directly::
 
     .. code-block:: xml
 
+        <!-- config/services.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -219,6 +227,7 @@ Another possibility is just setting public fields of the class directly::
 
     .. code-block:: php
 
+        // config/services.php
         use App\Mail\NewsletterManager;
         use Symfony\Component\DependencyInjection\Reference;
 
diff --git a/service_container/lazy_services.rst b/service_container/lazy_services.rst
index e38377f6b36..fe6ad427249 100644
--- a/service_container/lazy_services.rst
+++ b/service_container/lazy_services.rst
@@ -51,12 +51,14 @@ You can mark the service as ``lazy`` by manipulating its definition:
 
     .. code-block:: yaml
 
+        # config/services.yaml
         services:
            App\Twig\AppExtension:
              lazy:  true
 
     .. code-block:: xml
 
+        <!-- config/services.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -70,6 +72,7 @@ You can mark the service as ``lazy`` by manipulating its definition:
 
     .. code-block:: php
 
+        // config/services.php
         use App\Twig\AppExtension;
 
         $container->register(AppExtension::class)
diff --git a/service_container/parameters.rst b/service_container/parameters.rst
index 224684e84b9..046076a5fe5 100644
--- a/service_container/parameters.rst
+++ b/service_container/parameters.rst
@@ -17,11 +17,13 @@ Use the ``parameters`` section of a config file to set parameters:
 
     .. code-block:: yaml
 
+        # config/services.yaml
         parameters:
             mailer.transport: sendmail
 
     .. code-block:: xml
 
+        <!-- config/services.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -35,6 +37,7 @@ Use the ``parameters`` section of a config file to set parameters:
 
     .. code-block:: php
 
+        // config/services.php
         $container->setParameter('mailer.transport', 'sendmail');
 
 You can refer to parameters elsewhere in any config file by surrounding them
@@ -50,6 +53,7 @@ and hidden with the service definition:
 
     .. code-block:: yaml
 
+        # config/services.yaml
         parameters:
             mailer.transport: sendmail
 
@@ -59,6 +63,7 @@ and hidden with the service definition:
 
     .. code-block:: xml
 
+        <!-- config/services.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -78,6 +83,7 @@ and hidden with the service definition:
 
     .. code-block:: php
 
+        // config/services.php
         use App\Mailer;
 
         $container->setParameter('mailer.transport', 'sendmail');
@@ -116,7 +122,7 @@ and hidden with the service definition:
 
         .. code-block:: yaml
 
-            # app/config/parameters.yml
+            # config/parameters.yml
             parameters:
                 # This will be parsed as string '@securepass'
                 mailer_password: '@@securepass'
@@ -126,6 +132,7 @@ and hidden with the service definition:
 
         .. code-block:: xml
 
+            <!-- config/services.xml -->
             <parameters>
                 <!-- the @ symbol does NOT need to be escaped in XML -->
                 <parameter key="mailer_password">@securepass</parameter>
@@ -136,6 +143,7 @@ and hidden with the service definition:
 
         .. code-block:: php
 
+            // config/services.php
             // the @ symbol does NOT need to be escaped in XML
             $container->setParameter('mailer_password', '@securepass');
 
@@ -183,6 +191,7 @@ for all parameters that are arrays.
 
     .. code-block:: yaml
 
+        # config/services.yaml
         parameters:
             my_mailer.gateways: [mail1, mail2, mail3]
 
@@ -196,6 +205,7 @@ for all parameters that are arrays.
 
     .. code-block:: xml
 
+        <!-- config/services.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -225,6 +235,7 @@ for all parameters that are arrays.
 
     .. code-block:: php
 
+        // config/services.php
         $container->setParameter('my_mailer.gateways', array('mail1', 'mail2', 'mail3'));
         $container->setParameter('my_multilang.language_fallback', array(
             'en' => array('en', 'fr'),
@@ -247,12 +258,14 @@ Setting PHP constants as parameters is also supported:
 
     .. code-block:: yaml
 
+        # config/services.yaml
         parameters:
             global.constant.value: !php/const:GLOBAL_CONSTANT
             my_class.constant.value: !php/const:My_Class::CONSTANT_NAME
 
     .. code-block:: xml
 
+        <!-- config/services.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -267,6 +280,7 @@ Setting PHP constants as parameters is also supported:
 
     .. code-block:: php
 
+        // config/services.php
         $container->setParameter('global.constant.value', GLOBAL_CONSTANT);
         $container->setParameter('my_class.constant.value', My_Class::CONSTANT_NAME);
 
diff --git a/service_container/parent_services.rst b/service_container/parent_services.rst
index 4de1268c66e..ea23e2f6dff 100644
--- a/service_container/parent_services.rst
+++ b/service_container/parent_services.rst
@@ -63,6 +63,7 @@ duplicated service definitions:
 
     .. code-block:: yaml
 
+        # config/services.yaml
         services:
             App\Repository\BaseDoctrineRepository:
                 abstract:  true
@@ -81,6 +82,7 @@ duplicated service definitions:
 
     .. code-block:: xml
 
+        <!-- config/services.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -111,6 +113,7 @@ duplicated service definitions:
 
     .. code-block:: php
 
+        // config/services.php
         use App\Repository\DoctrineUserRepository;
         use App\Repository\DoctrinePostRepository;
         use App\Repository\BaseDoctrineRepository;
@@ -166,6 +169,7 @@ in the child class:
 
     .. code-block:: yaml
 
+        # config/services.yaml
         services:
             # ...
 
@@ -188,6 +192,7 @@ in the child class:
 
     .. code-block:: xml
 
+        <!-- config/services.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -220,6 +225,7 @@ in the child class:
 
     .. code-block:: php
 
+        // config/services.php
         use App\Repository\DoctrineUserRepository;
         use App\Repository\DoctrinePostRepository;
         use App\Repository\BaseDoctrineRepository;
diff --git a/service_container/service_decoration.rst b/service_container/service_decoration.rst
index 289a70ac70d..68071051e47 100644
--- a/service_container/service_decoration.rst
+++ b/service_container/service_decoration.rst
@@ -11,6 +11,7 @@ the original service is lost:
 
     .. code-block:: yaml
 
+        # config/services.yaml
         services:
             app.mailer:
                 class: App\Mailer
@@ -22,6 +23,7 @@ the original service is lost:
 
     .. code-block:: xml
 
+        <!-- config/services.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsd="http://www.w3.org/2001/XMLSchema-instance"
@@ -38,6 +40,7 @@ the original service is lost:
 
     .. code-block:: php
 
+        // config/services.php
         use App\Mailer;
         use App\DecoratingMailer;
 
@@ -55,6 +58,7 @@ that you can reference it:
 
     .. code-block:: yaml
 
+        # config/services.yaml
         services:
             app.mailer:
                 class: App\Mailer
@@ -73,6 +77,7 @@ that you can reference it:
 
     .. code-block:: xml
 
+        <!-- config/services.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsd="http://www.w3.org/2001/XMLSchema-instance"
@@ -94,6 +99,7 @@ that you can reference it:
 
     .. code-block:: php
 
+        // config/services.php
         use App\DecoratingMailer;
         use App\Mailer;
         use Symfony\Component\DependencyInjection\Reference;
@@ -127,6 +133,7 @@ replaces the ``app.mailer`` service. The old ``app.mailer`` service is renamed t
 
         .. code-block:: yaml
 
+            # config/services.yaml
             services:
                 app.decorating_mailer:
                     # ...
@@ -135,6 +142,7 @@ replaces the ``app.mailer`` service. The old ``app.mailer`` service is renamed t
 
         .. code-block:: xml
 
+            <!-- config/services.xml -->
             <?xml version="1.0" encoding="UTF-8" ?>
             <container xmlns="http://symfony.com/schema/dic/services"
                 xmlns:xsd="http://www.w3.org/2001/XMLSchema-instance"
@@ -158,6 +166,7 @@ replaces the ``app.mailer`` service. The old ``app.mailer`` service is renamed t
 
         .. code-block:: php
 
+            // config/services.php
             use App\DecoratingMailer;
             use Symfony\Component\DependencyInjection\Reference;
 
@@ -178,6 +187,7 @@ order by configuring the priority of decoration, this can be any integer number
 
     .. code-block:: yaml
 
+        # config/services.yaml
         foo:
             class: Foo
 
@@ -197,6 +207,7 @@ order by configuring the priority of decoration, this can be any integer number
 
     .. code-block:: xml
 
+        <!-- config/services.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
 
         <container xmlns="http://symfony.com/schema/dic/services"
@@ -218,6 +229,7 @@ order by configuring the priority of decoration, this can be any integer number
 
     .. code-block:: php
 
+        // config/services.php
         use Symfony\Component\DependencyInjection\Reference;
 
         $container->register('foo', 'Foo')
diff --git a/service_container/service_locators.rst b/service_container/service_locators.rst
index 83aebb5f9da..3d29293cc2b 100644
--- a/service_container/service_locators.rst
+++ b/service_container/service_locators.rst
@@ -15,7 +15,7 @@ using a CommandBus to map command handlers by Command class names and use them
 to handle their respective command when it is asked for::
 
     // src/CommandBus.php
-    namespace AppBundle;
+    namespace App;
 
     // ...
     class CommandBus
@@ -91,7 +91,7 @@ option to include as many services as needed to it and add the
 
     .. code-block:: yaml
 
-        // config/services.yaml
+        # config/services.yaml
         services:
             app.command_handler_locator:
                 class: Symfony\Component\DependencyInjection\ServiceLocator
@@ -150,7 +150,7 @@ Now you can use the service locator injecting it in any other service:
 
     .. code-block:: yaml
 
-        // config/services.yaml
+        # config/services.yaml
         services:
             App\CommandBus:
                 arguments: ['@app.command_handler_locator']
diff --git a/service_container/synthetic_services.rst b/service_container/synthetic_services.rst
index ee550947af1..94d93fdbdc8 100644
--- a/service_container/synthetic_services.rst
+++ b/service_container/synthetic_services.rst
@@ -35,14 +35,15 @@ configuration:
 
     .. code-block:: yaml
 
+        # config/services.yaml
         services:
-
             # synthetic services don't specify a class
             app.synthetic_service:
                 synthetic: true
 
     .. code-block:: xml
 
+        <!-- config/services.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -59,6 +60,7 @@ configuration:
 
     .. code-block:: php
 
+        // config/services.php
         // synthetic services don't specify a class
         $container->register('app.synthetic_service')
             ->setSynthetic(true)
diff --git a/service_container/tags.rst b/service_container/tags.rst
index af062070eb1..1e587630032 100644
--- a/service_container/tags.rst
+++ b/service_container/tags.rst
@@ -58,9 +58,9 @@ learn how to create your own custom tags, keep reading.
 Autoconfiguring Tags
 --------------------
 
-Starting in Symfony 3.3, if you enable :ref:`autoconfigure <services-autoconfigure>`,
-then some tags are automatically applied for you. That's true for the ``twig.extension``
-tag: the container sees that your class extends ``Twig_Extension`` (or more accurately,
+If you enable :ref:`autoconfigure <services-autoconfigure>`, then some tags are
+automatically applied for you. That's true for the ``twig.extension`` tag: the
+container sees that your class extends ``Twig_Extension`` (or more accurately,
 that it implements ``Twig_ExtensionInterface``) and adds the tag for you.
 
 .. tip::