Also, my .zig-cache is currently at 173GB, which causes some issues on the small Linux ARM VPS I test with.
As for upgrades. I upgraded lightpanda to 0.14 then 0.15 and it was fine. I think for lightpanda, the 0.16 changes might not be too bad, with the only potential issue coming from our use of libcurl and our small websocket server (for CDP connections). Those layers are relatively isolated / abstracted, so I'm hopeful.
As a library developer, I've given up following / tracking 0.16. For one, the change don't resonate with me, and for another, it's changing far too fast. I don't think anyone expects 0.16 support in a library right now. I've gotten PRs for my "dev" branches from a few brave souls and everyone seems happy with that arrangement.
I don't use zig. My experience has been that caches themselves are sources of bugs (not talking about zig only, but in general). Clearing all relevant caches occasionally is useful when you're experiencing weird bugs.
Do you see any major problems when you remove your .zig-cache and start over?