29 Days Left? 29 Days Till What? What Happens Then?

Hello.

I installed Bitdefender Antivirus (Free Edition) a couple of days ago. After installing it, I noticed that in the main window of the program, it says something about there being "29 days left." However, no further information or explanation is given.

My first thought was that the 29 days might be referring to a trial period of some kind, but this is supposed to be a fully-functioning free program not trialware, so I ruled that out. I also went back and checked the site where I downloaded it from to see if it said anything, but it doesn't. Not a single reference to "29 days" can be found anywhere on the site, so I have no idea what it means.

Does anyone know?