The update saying that there is a new version is a known bug.
Could be it is already solved in the latest beta.
https://forum.avast.com/index.php?topic=179656.0

Why do you change so often the program..
Because the bad guys keep developing new malware.

The old versions before 2014 where good, but they would not stand a change against nowadays malware and attacks.

If you can stop the bad guys from creating new things, avast would never have to be updated again :wink: