There are two mailing lists for unison, for general user discussion, and for development discussion. There is no intent to exclude anyone from the developers list; the point is to allow people who don't want those messages to not get them.

Note also that the github issue tracker is strictly for bugs and feature requests. Questions are off topic and issues that are questions will be summarily closed. If you think there might be a bug and you aren't sure, please ask on unison-hackers if your theory involves reading code, and either on unison-hackers or unison-users if your theory doesn't involve code references.

unison-users is a higher-volume discussion forum for users of unison. It is used for discussions of many sorts --- proposals and designs for new features, installation and configuration questions, usage tips, etc. Generally, if the discussion requires an understanding of the current code base, it is more apppriate on -hackers. unison-users is moderated to filter spam, so you should not expect your postings to appear immediately. As with most lists, it requires subscription to post.

This list is hosted by google groups, but does not require a google account to join. To join the list, send an email to unison-users+subscribe@seas.upenn.edu. In 2022-11, there was one report that the method to join without a google account does not work, and one report that it did.

To post to the list, send to unison-users@seas.upenn.edu

As of 2020-10, there are roughly 1200 subscribers.

(Note that there used to to be a unison-users mailman group at lists.seas.upenn.edu, and you may still find pointers to it lying around on the web. It has been deleted in favor of the Google group.)

unison-hackers is for informal discussion among people seeking to improve Unison. Anyone who wishes to lend a hand with maintaining and improving Unison is welcome to join, and that translates to "anyone would like to join is welcome". Only members can post.

unison-hackers is managed with the Mailman mailing list server. To subscribe, visit http://lists.seas.upenn.edu/mailman/listinfo/unison-hackers

As of 2020-10 there are roughly 275 subscribers.