First, I want to thank you for continued enhancements and support for the 8800 series IP Phones. It was a rough start but it is really starting to shine. Previously your team mentioned the "Big Green Button" which completely aligns with OBTP (One Button to Push) from the Tandberg realm. The ability to select one button to join your scheduled meeting ensures adoption of your services. According to your Cisco team, OBTP is present for only cloud registration. Please allow this feature to trickle down to the on-prem deployments! No one is asking for completely new code or features to be fabricated. I'm sure the entire community would appreciate this capability.
This article shows "On-premises devices that are registered to Cisco Unified Communications Manager", regarding OBTP.
It requires on-prem TMS.