Should I upgrade from avast! 4.8 to a newer one?

[REDACTED]

Should I uninstall my avast! 4.8 Professional and install the latest avast! Free Antivirus? My avast! 4.8 has a registration key which expires on 2015, but I'm not sure if I'm fully protected because avast! 4.8 Professional is an old software... If I'm not fully protected by this, my choice is to uninstall this and just install the latest avast! free antivirus.

So to sum all up, which is better?
a.) avast! 4.8 Professional with a registration key
OR
b.) the latest avast! Free antivirus 2014 which has a FREE license

btw, I'm running on Windows 7 x64 Home Basic if that helps...

[Pondus]

Should I uninstall my avast! 4.8 Professional and install the latest avast! Free Antivirus?

yes ..... there is lots of stuff the old AV engine does not detect

[REDACTED]

hmm... well is there any way I could just somehow disable my avast! 4.8 Professional before I install the latest avast! Free Antivirus? I want to make sure that I could still use avast! 4.8 later after installing the latest avast! Free Antivirus, because I had an issue with my other PC wherein after I install the latest avast! Free Antivirus, avast! 4.8 Professional's resident protection no longer works and cannot be turned on even when I turn the latest avast! Free Antivirus's resident protection off...

[CraigB]

The new version "free" has better protection than the older 4.8 Pro version and my recommendation would be to completely remove 4.8 before installing the new to avoid any issues.

[bob3160]

Your question is about the same as should I update from Windows XP.
Great strides have been made in your protection in both your AV program and your Operating System.
Both should be as up to date as possible for the greatest protection.
Stop fighting your battles with a slingshot when rockets are available. 
Keeping version 4.8 is not a good idea even if that were possible.
Never run more than one resident AV at the same time.
Hope that helps.