docs: update autodiscovery guide

docs/autodiscovery.rst

@@ -1,18 +1,73 @@
 Autodiscovery
 =============
 
-`RFC6186 <https://www.rfc-editor.org/rfc/rfc6186>`_ allows supporting email clients to automatically discover SMTP / IMAP addresses
+`RFC6186`_ defines how email clients can automatically discover a mail server's
-of the mailserver. For that, the following records are required:
+SMTP and IMAP endpoints. To enable this, the following DNS records must be
+configured:
 
-================= ==== ==== ======== ====== ==== =================
+.. csv-table:: Resource record set
-Record            TTL  Type Priority Weight Port Value
+   :header: "Name", "TTL", "Type", "Priority", "Weight", "Port", "Value"
-================= ==== ==== ======== ====== ==== =================
+   :widths: 30, 5, 5, 5, 5, 5, 20
-_submission._tcp  3600 SRV  5        0      587  mail.example.com.
-_submissions._tcp 3600 SRV  5        0      465  mail.example.com.
-_imap._tcp        3600 SRV  5        0      143  mail.example.com.
-_imaps._tcp       3600 SRV  5        0      993  mail.example.com.
-================= ==== ==== ======== ====== ==== =================
 
-Please note that only a few MUAs currently implement this. For vendor-specific
+   _submissions._tcp.example.com., 3600, SRV, 10, 1, 465, mail.example.com.
-discovery mechanisms `automx <https://github.com/rseichter/automx2>`_ can be used instead.
+   _imaps._tcp.example.com., 3600, SRV, 10, 1, 993, mail.example.com.
 
+
+Legacy records
+^^^^^^^^^^^^^^
+
+The following DNS records are only supported with
+:option:`mailserver.enableSubmission` and :option:`mailserver.enableImap`,
+because they only support connections with explicit TLS. These services are
+disabled by default because they are deprecated through `RFC8314 4.1`_.
+
+.. csv-table:: Resource record set
+   :header: "Name", "TTL", "Type", "Priority", "Weight", "Port", "Value"
+   :widths: 30, 5, 5, 5, 5, 5, 20
+
+   _submission._tcp.example.com., 3600, SRV, 20, 1, 587, mail.example.com.
+   _imap._tcp.example.com., 3600, SRV, 20, 1, 143, mail.example.com.
+
+Client support
+^^^^^^^^^^^^^^
+*As researched in March 2026*
+
+Only a small number of MUAs currently implement this. The most common concern
+from the bigger and security-conscious vendors is lack of widespread DNSSEC
+propagation that could be used to authenticate these SRV records.
+
+- Aerc: since 0.20.1
+
+  - ``_submissions._tcp`` support submitted in https://lists.sr.ht/~rjarry/aerc-devel/patches/68173
+
+- Evolution: Since 3.49.3 for mail accounts
+
+  - https://gitlab.gnome.org/GNOME/evolution/-/wikis/Autoconfig
+  - https://gitlab.gnome.org/GNOME/evolution/-/issues/941
+
+Unsupported
+***********
+- DeltaChat:
+
+  - https://github.com/chatmail/core/issues/1508
+
+- Thunderbird:
+
+  - Desktop: https://bugzilla.mozilla.org/show_bug.cgi?id=342242
+  - Android: https://github.com/thunderbird/thunderbird-android/issues/4721
+
+
+Vendor-specific autoconfig
+^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The `automx2`_ service can provide autoconfig support for Apple's
+`mobileconfig`_, Microsoft's `Autodiscover`_ and Mozilla's `Autoconfig`_
+standards. It does however lack support for multiple mail domains and isn't open for
+contributions due to copyright concerns.
+
+.. _mobileconfig: https://support.apple.com/de-de/guide/profile-manager/pmdbd71ebc9/mac
+.. _Autodiscover: https://learn.microsoft.com/en-us/exchange/architecture/client-access/autodiscover?view=exchserver-2019
+.. _Autoconfig: https://benbucksch.github.io/autoconfig-spec/draft-ietf-mailmaint-autoconfig.html
+.. _automx2: https://github.com/rseichter/automx2
+.. _RFC6186: https://www.rfc-editor.org/rfc/rfc6186
+.. _RFC8314 4.1: https://www.rfc-editor.org/rfc/rfc8314#section-4.1