That would appear not to be the only restriction, see extract from their download page below.

Important notices
AVG Free Edition is available in English language only.

AVG Free Edition offer is valid for all SINGLE HOME users only.

AVG Free Edition CAN NOT BE INSTALLED ON SERVERS FOR ANY REASON. IT CAN NOT BE INSTALLED IN ANY NETWORKED ENVIRONMENT!

NO TECHNICAL SUPPORT IS AVAILABLE WITH AVG Free Edition.

From what I can see the free version is still AVG 6.

The AVG 7 is a trial download which you will have to pay for or uninstall after trial period.

David