When I enabled notifications in settings on Serbian Wikipedia, related to ping to be showed on web version of Wikipedia, I got this and I can't get rid of this notifications even I click mark as read:
Ok, I found a solution. I marked as read each group of 50 notifications, it was 343.
So I get rid of these notifications.
But we should found a bug, how I can get notifications which are 2 years old after changing settings related to notifications for ping.