Hello, same problem here. It seems that @Helge Meinhard workaround WORKS. Thanks!
In my case: Workstation: Xubuntu Focal 20.04 LTS Laptop.....: Xubuntu Bionic 18.04 LTS Server.....: Debian 10 Buster (1) I didn't uninstall unison unison-all unison-all-gtk from Focal (2) I copied the binaries /usr/bin/unison-2.48.4 and /usr/bin/unison-2.48.4-gtk from Bionic to Focal (3) I deleted all ~/.unison/fp* (in all machines) Various tasks between Focal and (Bionic or Buster) are working. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1868502 Title: Synchronization with earlier Ubuntu versions or a recent Debian version fails To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/unison/+bug/1868502/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs