You Can Update/Upgrade from 7.1 to 7.5 on AVG

You can keep your 7.1 version and download the 7.5 version of AVG..

During the install routine, I think you'll see a "repair" installation option,
select this one and it will upgrade your 7.1 to 7.5, without having to
uninstall/ and then reinstall...

Just my two cents....