Do you really care about the copyright year?
As you've made changes to the codebase in 2021, you're entitled to
update the copyright year. But I'd rather not do it if you don't care
that much, keeping the copyright lines up-to-date is a pain.
I agree with Simon, it's not worth the bother. I don't want to see
trivial copyright year patches to all my projects every year. It's a bad
habit.
--
delthas