Firefox 57.0 Avast Online Security 10.3.3.4 (legacy) disabled

Hi
as the subject informs, this is the message I see in Tools, Addons.
In Chrome I see a green tick next to each url a browser search retrieves but this is not working in the latest Firefox.
Is a fix anticipated soon?
I have iMac 7.1 osx 10.11.6
Avast Security
vir def 17112014
prog ver 12.9

Same Issue here
Imac osx 10.13.1
Avast 12.9