Are you using avast! Home Edition ?
If your answer is YES, then my answer is also YES. Updates will stop after that date. All you have to do is to re-register your Home Edition again after that date and that's it. Your updates will be ready for downloading again...
This is very small price you have to pay, and you get such a great freeware product. Registering is just for statistics purposes, so Alwil guys can track how many people are using their wonderful product. As you can see, no personal information is required during registration process...