The title pretty much says it all, but I'll repeat in the body with more detail.
When notification feed notification:user1 follows flat feed posts:user2, activities are copied from posts:user2 to notification:user1. The precise number of activities to be copied can be optionally specified by passing an activityCopyLimit integer.
However, when a feed unfollows another feed, there is no similar option to control this behavior. The documentation simply states:
Existing activities in the feed coming from the target feed will be purged (asynchronously)
So my question is: is this also the case when it comes to notification feeds?
Whether it is or not, the option to not purge activities would be very useful. Just because a user no longer needs to receive activities from a given feed doesn't necessarily mean that the history of what has been received should disappear.
Thanks much.
It is possible to not purge the history when unfollowing feeds using the keep_history parameter. This feature is still not available on all official clients but it is described in the API rest documentation. The parameter needs to be provided as part of the query parameters and have value true or 1. If your client is not yet supported, you should open a ticket on its Github repository.