I don’t have a list of whats planned for 8.9 or 9.0 fixes. Notifications is one of the top things I am trying to push for.. along with a number of other items that were meant to be resolved in 8.8
To that, there are a number of tech debt tasks we are required to complete in the next few updates which have taken a chunk of what little capacity we have. The unfortunate effect of that is, some fixes and changes we want to make an release, get pushed out.
I know the notification issue is one of the older ones, and it appears to not be an easy fix from what the team have explained to me. They are aware though and do want to get it sorted, but these tech changes have push that task back.