[seoulbigchris]

> A few apps have complained about the older OS; so far I've been able to react by deleting the apps.

Not about the phone (I have iPhone 12), but I have an app called Trunk Notes which is a wiki reader / editor. It was one of the only wiki apps I found that could work cooperatively with my own markdown vimwiki that I keep on my desktop (and sync via Dropbox or similar).

A few years back, it complained that it would no longer work in iOS version something-or-other and the author apologized because he could no longer maintain it. I never got around to deleting it, and to my surprise it still works to this day.