I did a bad thing.
This project is aimed at macOS 13 Ventura and higher. Back-porting to macOS 12 may be possible but would be a lot of work. Pull requests would be welcome but macOS 12 and older support is not and likely won't be a priority.
While it can compile and run on iOS 16 devices it has not been tested on any iOS devices at all. Focus is getting mac OS support running first - then bringing up iOS (and especially iPad) support.
See https://github.com/schwa/MastodonAgain/projects for more.