diff --git a/symfony/mailer/4.3/manifest.json b/symfony/mailer/4.3/manifest.json
index 826add361..84181b0d2 100644
--- a/symfony/mailer/4.3/manifest.json
+++ b/symfony/mailer/4.3/manifest.json
@@ -4,6 +4,5 @@
     },
     "env": {
         "#1": "MAILER_DSN=smtp://localhost"
-    },
-    "aliases": ["mailer", "mail"]
+    }
 }
diff --git a/symfony/mailer/4.3/post-install.txt b/symfony/mailer/4.3/post-install.txt
index 92097aae5..0c79ff838 100644
--- a/symfony/mailer/4.3/post-install.txt
+++ b/symfony/mailer/4.3/post-install.txt
@@ -8,4 +8,11 @@
     the corresponding bridge.
     For instance, <info>composer require mailgun-mailer</> for Mailgun.
 
+  * If you want to send emails asynchronously:
+
+    1. Install the messenger component by running <info>composer require messenger</>;
+    2. Add <info>'Symfony\Component\Mailer\Messenger\SendEmailMessage': amqp</> to the
+       <info>config/packages/messenger.yaml</> file under <info>framework.messenger.routing</>
+       and replace <info>amqp</> with your transport name of choice.
+
   * <fg=blue>Read</> the documentation at <comment>https://symfony.com/doc/master/mailer.html</>
diff --git a/symfony/swiftmailer-bundle/2.5/manifest.json b/symfony/swiftmailer-bundle/2.5/manifest.json
index 12b9f3f71..0dc856793 100644
--- a/symfony/swiftmailer-bundle/2.5/manifest.json
+++ b/symfony/swiftmailer-bundle/2.5/manifest.json
@@ -10,5 +10,6 @@
         "#2": "For a generic SMTP server, use: \"smtp://localhost:25?encryption=&auth_mode=\"",
         "#3": "Delivery is disabled by default via \"null://localhost\"",
         "MAILER_URL": "null://localhost"
-    }
+    },
+    "aliases": ["mailer", "mail"]
 }