This new system is being trialled, it currently isn’t widespread, I have been using avast free for over 12 years, yet I haven’t seen anything on the need or lack of registration with the free version. So not many forum users will have seen this either.
But as far as I’m aware you will have to register for the first time (presumably as you would have to setup your my.avast.com account), but not every subsequent year. Unless they are just seeking to have a current/valid email address.