Fax For Asterisk in Asterisk 13

I was checking Fax receiving capability per extension
I played around successfully some months (years) ago,
Now it’s not working anymore , I was investigating when a banner appeared in FaxOptions menu :

You are running Asterisk 13 which does NOT support Fax for Asterisk. If availible spandsp will be used instead.

Yes I switched to Asterisk13 lately…

How can I proceed now ??
What about spandsp, how to implement it ??

Thanks

If you are on the distro you should be OK.

Otherwise look at http://www.asteriskguru.com/tutorials/spandsp.html