> Headscale is ... drop in replacement

I've been really happy with headscale, but I wouldn't call it a complete drop in replacement as I would with vaultwarden. Some features (e.g. Mullvad integration, ACL tests, etc) are missing.

Upgrading also requires upgrading every minor version or you run into db migration issues, but that comes with the territory of running your own instance.

I would recommend folks look up if headscale suits their needs (like it did for me for many years) before switching over.