diff --git a/UPGRADE-5.0.md b/UPGRADE-5.0.md
index e821a0a1382dd..a412326a12257 100644
--- a/UPGRADE-5.0.md
+++ b/UPGRADE-5.0.md
@@ -490,6 +490,7 @@ SecurityBundle
    changed to underscores.
    Before: `my-cookie` deleted the `my_cookie` cookie (with an underscore).
    After: `my-cookie` deletes the `my-cookie` cookie (with a dash).
+ * Removed the `security.user.provider.in_memory.user` service.
 
 Serializer
 ----------
diff --git a/src/Symfony/Bundle/SecurityBundle/CHANGELOG.md b/src/Symfony/Bundle/SecurityBundle/CHANGELOG.md
index 0455d270c9d2a..11c47f822879a 100644
--- a/src/Symfony/Bundle/SecurityBundle/CHANGELOG.md
+++ b/src/Symfony/Bundle/SecurityBundle/CHANGELOG.md
@@ -15,6 +15,7 @@ CHANGELOG
  * Removed the `threads` encoder option
  * Removed the `security.authentication.trust_resolver.anonymous_class` parameter
  * Removed the `security.authentication.trust_resolver.rememberme_class` parameter
+ * Removed the `security.user.provider.in_memory.user` service.
 
 4.4.0
 -----
diff --git a/src/Symfony/Bundle/SecurityBundle/Resources/config/security.xml b/src/Symfony/Bundle/SecurityBundle/Resources/config/security.xml
index ff4fbf3655b6e..0408a48077f50 100644
--- a/src/Symfony/Bundle/SecurityBundle/Resources/config/security.xml
+++ b/src/Symfony/Bundle/SecurityBundle/Resources/config/security.xml
@@ -183,9 +183,6 @@
         </service>
 
         <service id="security.user.provider.in_memory" class="Symfony\Component\Security\Core\User\InMemoryUserProvider" abstract="true" />
-        <service id="security.user.provider.in_memory.user" class="Symfony\Component\Security\Core\User\User" abstract="true">
-            <deprecated>The "%service_id%" service is deprecated since Symfony 4.1.</deprecated>
-        </service>
 
         <service id="security.user.provider.ldap" class="Symfony\Component\Ldap\Security\LdapUserProvider" abstract="true">
             <argument /> <!-- security.ldap.ldap -->
diff --git a/src/Symfony/Bundle/SecurityBundle/Security/LazyFirewallContext.php b/src/Symfony/Bundle/SecurityBundle/Security/LazyFirewallContext.php
index ef9b1e217cd5a..78ee1f275e28c 100644
--- a/src/Symfony/Bundle/SecurityBundle/Security/LazyFirewallContext.php
+++ b/src/Symfony/Bundle/SecurityBundle/Security/LazyFirewallContext.php
@@ -51,12 +51,7 @@ public function __invoke(RequestEvent $event)
         $this->tokenStorage->setInitializer(function () use ($event) {
             $event = new LazyResponseEvent($event);
             foreach (parent::getListeners() as $listener) {
-                if (\is_callable($listener)) {
-                    $listener($event);
-                } else {
-                    @trigger_error(sprintf('Calling the "%s::handle()" method from the firewall is deprecated since Symfony 4.3, implement "__invoke()" instead.', \get_class($listener)), E_USER_DEPRECATED);
-                    $listener->handle($event);
-                }
+                $listener($event);
             }
         });