Mozilla has 64-bit firefox in its ftp server for download for months (I don’t remember starting from which version).
She kept all versions as beta and never release the final…just the final :wink:
Avast add-on has worked fine with 32-bits firefox but not with 64-bit as I known and tried myself.
Today, Mozilla released a candidate copy of 64-bit version 42 and they have never did before.
So, I think Mozilla is going to start release offical copy of 64-bit firefox.
If my experience with 64-bit version is correct, then Avast has to do something…