approximately 3 months before I bought for a friend’s license number avast 4.8 and now it went to version 5.0 but will likely not take his license key. Must be to generate some special key to avast 5 using his credentials? How to be inserted into the license key version 5? Thank you for quick answer
I was using this link when I moved from v4.8 Pro to Pro Antivirus v5
ohhh i guess i didn’t have to buy it again 
Correct, as long as your license is valid