Hello ManyQs,
Welcome back.
Avast 5.0 has been out for a while. Although it had issues in the beginning, guys at avast have rectified them and we are almost close to a perfect version 5. I loved 4.8 much until I really switched to v5, although I did have a few installation issues. According to my knowledge, v4 will be supported until v5.1 is out. Dont ask me what is the actual date when 5.1 will be released, but there is actually a post regarding this in avast blog : blog.avast.com . Keep track of it. I would suggest you upgrade to v5 now-better detection, look, interface etc.. But if you wish to wait until v5.1 is released, its your wish.
Good day.
nmb