Mail Archiver 5.3.4 has been released
Archiving from Outlook and Gmail accounts from Mail doesn't work on AppleSilicon. Mail Archiver hangs and doesn't do anything.
Version 5.3.4 adds a message to the app log and MAX no longer hangs:
The problem occurs deep within the bowels of macOS and there is no direct workaround. Archiving from IMAP works fine, though. Everything is working for version 6 which is coming in a few weeks.
This version also fixes a couple of minor bugs.