Change minimum password length AFTER the fact?

hello! I have a couple of sites that have quite a few members now. In looking at what I originally set as the minimum password length, I believe I have it set to low. If I change the minimum password length setting now, will this take effect for all NEW users, or will it cause some sort of issue for already active accounts who may have passwords shorter than the new rule?

It will only affect new users or old users when they change in their profles.

David