I run Syncthing on all of my devices, namely my primary workstation (Manjaro Linux), laptop (EndeavourOS), second desktop (Bodhi Linux), phone (/e/ OS), and tablet (LineageOS). I was upgrading a laptop with Linux Mint 20.04 to 22.04. On Ubuntu-based Linux distributions, I use the Syncthing PPA instead of the version of Syncthing in the Ubuntu repositories. The Mint upgrade removed the Syncthing PPA that had been installed in the previous version and (I think) replaced Syncthing with the default Ubuntu repository version. Shockingly (I wasn’t shocked), Syncthing was not working after the upgrade (the upgrade otherwise went very smoothly, however – credit to the Mint team for a job well-done). The problem was more than easy enough to solve: Carefully follow the official Syncthing instructions for adding the PPA (do not forget to note whether you are adding the stable or candidate version of Syncthing and make sure to study the troubleshooting section). The Syncthing guidance also applies to Debian and distributions based on Debian.