I have wasted an entire day going back and forth between Ring Central support and Polycom support as I've been trying to setup my Polycom VVX 410 handset with my RC MVP seat.
Ring Central wants me to downgrade the firmware on my VVX 410 to Version 5.6.0.20009, which was released in July 2017. Polycom said that they don't support this version anymore, and they don't have a "custom server" where I could grab the software using the Poly Web Configuration Utility.
This phone worked great with Ring Central before I set it up with Microsoft Teams a few months ago. Now I am trying to move it back to Ring Central but I am not having luck.