I had OpenVPN server installation on my server through sysadmin module pro. I has some phone with openvpn client build-in, but the openvpn client version of these phone are old (2.0.x). The openvpn server come with the sysadmin pro is newer (2.3.x). So the server config file contains some parameter which the older openvpn client does not recognize. So I tried to modify the server config file for that the older client version can connect to the server. The server config file located at /etc/openvpn/sysadmin_server1.conf. However the file be overwritten with default setting whenever I create new openvpn client or change server setting from freepbx GUI. Where is the default setting be stored? How can I change the server config file permanently?