I'm not sure where to find the APKs/IPAs, but once you do, I wonder if using Claude Code or some other LLM tools could help you update the app (or reverse engineer) for modern OS versions. It's something that I've been thinking to do for my 2012 obsoleted microjournaling app.

They could, but then so can a lot of tools. At least with Android, it’s still Java so you can just emulate the runtime and run the app. To upgrade, just decompile the Java bytecode back into something editable.

I had this same issue with one of my “long lost” games only, it wasn’t a mobile game but a console game, so Ghidra was my only hope.