FreePBX will then perform a reload and re-write all the configuration files based on the version of Asterisk you switch to.
You can verify the running version of Asterisk at the bash prompt with:
# asterisk -x "core show version" Asterisk 13.9.1 built by mockbuild @ jenkins2.schmoozecom.net on a x86_64 running Linux on 2016-05-13 20:33:39 UTC
If the old Asterisk version is still shown, you can restart with:
The final step is to reload the system dial plan: