Yeah, I kinda held on to the old version for a while too TBH, syncthing-fork had a problem where I couldn't get it to work the way I wanted it, so I'd gone back to syncthing, then with all the kerfuffle, I just stayed there.
Some time earlier this year I tentatively upgraded 1 phone and a tablet (it's used as slideshow screensaver...) and it all seems to work ok.
The GUI isn't quite as good as the native webUI, but it's still accessible, so all's good.
There was a change in the syncthing "DB" a while ago, so it might take a while to rescan things if you have a lot of small files, but feel confident to change.
Didn't Men At Work have a song about a land yundera?
https://youtu.be/XfR9iY5y94s