switched to sf.net mailing list

docs/mailing_list.md

@@ -1,7 +1,17 @@
 The WEKA Mailing list can be found here:
 
-* [List](https://list.waikato.ac.nz/postorius/lists/wekalist.list.waikato.ac.nz) for subscribing/unsubscribing to the list.
-* [Archives](https://list.waikato.ac.nz/hyperkitty/list/[email protected]/) ([Mirror 1](https://weka.8497.n7.nabble.com/), [Mirror 2](https://marc.info/?l=wekalist)) for searching previous posted messages.
+* [List](https://sourceforge.net/projects/weka/lists/weka-users) for subscribing/unsubscribing to the list.
+* [Archives](https://sourceforge.net/p/weka/mailman/weka-users/) for searching previous posted messages.
 
 
 Before posting, please read the [mailing list etiquette](https://ml.cms.waikato.ac.nz/weka/mailinglist_etiquette.html).
+
+Once you have subscribed to the list (a moderator may have to approve your request), you can send posts to the list
+using the following email address:
+
+```
+[email protected]
+```
+
+**NB:** The mailing list moved to Sourceforge.net in mid-December 2024, due to
+the university mailman server being decommissioned. You can find the old archives [on this mirror](https://marc.info/?l=wekalist).