I pushed an update to Aperture which allows you to toggle per-channel whether read state tracking is enabled. There are two modes, one where it returns the count of the number of unread items, and the other where it returns only true or false depending on whether there are new items.
For my super busy feeds, it wasn't useful having the counts, but I do like a subtle indicator there are new posts.
There are also some channels I don't want to be bothered about at all, so I've disabled read state tracking on those.
This means the Microsub API is now returning either an integer or a boolean for the unread property on channels, e.g.: