The music is mid 1800s, the original “good morning” lyrics are late 1800s, but the “happy birthday” lyrics are early 1900s. Even then, no copyright notice occurred for years. Technically, the song isn’t under copyright because back then you needed to have a copyright notice. Not only that, but the “good morning” lyrics are in the public domain, and there is a good legal doubt that simply substituting “happy birthday” constitutes a copyrightable derivative.
I wonder what some of our more racist songs bring in?<.p>