Help regarding Using older version of Avast

Hello eveyone,
I have a question regarding using Avast6.0 free version. Is it possible to update Avast 6.0 free version program with current virus database definitions if we have a valid license. I have an old PC and Avast 7 and 8.0 versions are a big drag on that system.If i install Avast 6.0 free and register it, will it update definitions (no program update in my case) and work properly.
Ankit

Yes.