The team is working on the API, and we will post as we have more information.
In the meantime, for Embrava, please note they have announced presence support for TeamsOnly mode with their version 5.2.16.Brett Bogler commented
Hey Alex, How has this gone for almost a year and still nothing available?
This has two parts:
Busy on Busy: This feature is released, please see the documentation below for admin configuration to enable this.
Voicemail on Busy – This feature is on the backlog. We’ll update when we have more details to share.