What happens when the created work is edited? Is there some threshold of trivial edits below which you can't change the year in the notice? I mean presumably

What happens when the created work is edited? Is there some threshold of trivial edits below which you can't change the year in the notice? I mean presumably if you do edit it, people still have the right to use older versions when the copyright expires. But how does that play with the requirement to give notice?