Cannot extend free Avast Antivirus

I am running program version 18.4.2338 (build 18.4.3895.327). My Avast free user license just expired. I tried updating it, but I am only given the option to buy a paid version. I’ve tried logging into my user account and extending it from the website as well, but there is no option to extend my free avast. What am I doing wrong?

Thanks for your help with this question.

Update to the latest version (18.6.2349): https://forum.avast.com/index.php?topic=221320.0