Today DC supports the notifications for the posts' updates. It means if someone changes the post text, title, group or tag you can be notified about that.
But this notifications just inform that there were updates, but do not show what exactly was changed in the post.
So through this, you can get the notifications for the posts from previous years without any reason what's happened.
I would suggest to turn off this types of notifications until we'll implement the details in notifications, what exactly was changed in the post and why did you get it.