Luckily the app is generally (but not always) backwards compatible. It’ll just nag you to upgrade the server.

The server doesn’t, except if you have watchtower or something similar.

The app auto updates on your phone though, unless turned off.

Like everyone is saying, Immich.

But keep an eye on updates because it is under active development so breaking changes tend to happen every once in a while.

One of the things I like about DDG is that you can turn localised results on/off whenever you like and even chose the location. Also localised search is pretty good for me too.