Latest avast! Free AV says not compatible with Windows 8.1

[Matrix Leader]

I was told on these forums that avast! Free Antivirus 8.0.1497.376 is compatible with Windows 8.1

I installed it and as soon as it started I got a message saying that it is not compatible with my OS although it seems to be working fine.

Furthermore, when I launch IE11, it says the addons are not compatible

I don't use IE, but also it doesn't install the addons for Pale Moon which is a Firefox Variant, anyone knows the solution to the first question and how to manually install the avast addons in my Pale Moon? where are they located so I can manually install them from Pale Moon?

[Eddy]

Upgrade to avast 2014-RC2 and see if it solves the problem.
FireFox is supported, Pale-Moon is not since it is not the same as Firefox

[Asyn]

I installed it and as soon as it started I got a message saying that it is not compatible with my OS although it seems to be working fine.

You can safely ignore the MS message.