Is it fair to assume that most user-agent devices such as Polycom VVX phones, Yealink Phones currently do NOT support these new protocols? What about support from voice switches (broadworks). Do they know how to process the new headers appropriately?

1. General Battling Robocallers with STIR/SHAKEN
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We expect that the UC/IP-PBX developers will be using the “verstat” tag to implement a form of screening or routing before the call is delivered to their IP Phones. However, IP phones have more limited displays – how they decide to display the verification status is TBD.