I've been playing in a part of the sandpit where I'm getting interested
in SystemChangeNotifier. There was mention some time ago of refactoring
it to use Announcements. Did that end up going anywhere? Is there
anything I should look at before I roll up my sleeves and get stuck in?

Also, quite separately, are there plans to have Announcements in core
Squeak any time soon?

Regards,
  Tony