If you've been getting incompatible_destination on your siproutes calls, it seems some underlying carrier can no longer handle type 13 from CNG.
If you have a gateway file for siproutes, you can simply add:
<param name="supress-cng" value="true"/> (It's also accessible in the advanced options in fusionpbx)
They also recommend setting <param name="auto-rtp-bugs" value="clear"/> because of sonus, but I can't find on the wiki what that does.