Ralf Hildebrandt writes:
Absolutely. Topics of interest to me would include:
- what has changed (GUI?)
Already in the beta distribution. But briefly, "everything's all-new, all-shiny." There will be mailman2-to-mailman3 migration scripts, of course, but the admin and archive websites are completely new. They are functionally similar so will seem somewhat familiar, of course, and where possible Postorius maintains a similar layout, I think.
Where else do you expect to find this information, so we can put it there?
- how can I install mm2 and mm3 side by side (if possible at all, I'd like to be able to switch back an forth if the shit hits the fan)
Uh, just do it?
Of course it will be MTA-specific. I haven't done it on Postfix, but for Exim you just add a Mailman3 router and transport ahead of the Mailman2 router (I've already submitted the docs for that -- they're very generic -- don't know if Barry's merged them yet), and start adding Mailman3 lists. To reverse migrate, make sure the relevant "is this a mailman3 list" config file is moved out of the way if you want to switch a migrated list back to Mailman2.
For Postfix, I suppose you have to mess with the aliases directly.
Caveats: (1) I have no idea about importing archives from HyperKitty into Mailman2. (2) Reverse migration preserving configuration will not be trivial -- you'll have to keep the original configs around for lists that migrate from Mailman2 to Mailman3, and make new ones for lists newly created on Mailman3. We could make scripts for (2), but I wouldn't trust them very much, they're not going to get a lot of testing.