Downgrade issues

NixOS und Nix support downgrades. That works mostly without issues, but some software complain when their state was created with a newer version. This page exist to collect those cases.

Note: If you know a program that does not work well after a downgrade, please add it here with it's behavior and error message if possible.

Syncthing

Refuses to start when downgraded.

[root@nixos:~]# journalctl -u syncthing.service
...
WARNING: Failed to initialize config: config file version (36) is newer than supported version (35). If this is expected, use -allow-newer-config to override