Since WordPress seems to be recommending the move to 7.X, is it reasonable and desired to install that instead? Even if it is not in the official repositories? (I am, just asking for future reference for others.)
I would install this on Fedora today. If you want to be on CentOS 7, then install the Remi repo and enable the PHP 7.1 repo.
Often sales people and management will ask, "How do I check my voicemail from outside?" I always recommend that they enable voicemail to email, but for those that want it, you can set up a silent option in the IVR.
What I mean by silent option is that you will add another option to the IVR, but you will not announce that option in the recorded audio.
Add another entry and choose the Destination category of Feature Code Admin and then select Dial Voicemail <*98>
Some people have reported issues using the PJSIP settings with VoIP.ms. I have been using it for months with no problems, but if you are having problems, then you can create a CHAN_SIP based trunk with no problems.
We run one OC system that is used for a client that has clients that need to move files to and from them from loaned hardware. It's a weird, complicated scenario. But OC works beautifully for it and has for years.