There is only one notification type in Newsletter: subscribe-newsletter
/me is intrigued, trying to understand the description and the parent task. In any case, thank you for helping improving the Newsletter extension! "Catrope filed a task in our project " is almost a milestone. ;)
Looks like Echo's formatting system was rewritten and Newsletter extension's formatter also needs to be updated to use the new system. Is there any documentation on how to migrate to the new system?
Yes, @Glaisher has it right. We (collaboration team) are going through all extensions and porting them to the new system (since we are the ones that decided to introduce it). So you guys don't have to do anything, unless you want to :) (in which case please assign this task before one of us claims it)