To upgrade from Asterisk 16 to 18

1. If Enswitch is at version 4.1 or earlier, first upgrade to 4.2.
2. Make sure the latest Enswitch fixes are installed.
3. Do:
   • ls -l /usr/lib/asterisk/modules/codec_g729* # To check if G.729 is in use.
   • mv /usr/lib/asterisk/modules /usr/lib/asterisk/modules-16
   • enswitch install -u asterisk-18
4. If using G.729:
   • enswitch install -u g729-18
5. In /etc/asterisk/extensions.conf, change "extensions_enswitch_16.conf" to "extensions_enswitch_18.conf".
6. On the Enswitch web interface, under Global » Settings » Configuration, set "Asterisk version" to "18".
7. Reboot the Asterisk machine.
8. Test calls.