Hello @mrbird ,
Welcome back to the Poly Community.
Usually, the Microsoft SKU aka -019 is more expensive to cover the Poly per device Skype for Business License.
I believe on the Trio Family we do not make this mandatory and the phone, as already noticed, after a factory reset will be in openSIP mode and use DHCP option 160 instead of the Skype/Teams version option 161.
Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.
Best Regards
Steffen Baier
----------------
The title Polycom Employee & Community Manager is a community setting and does not reflect my role. I am just a simple volunteer in the community like everybody else. My official "day" Job is 3rd Level support at Poly but I am unable to provide official support via the community.
----------------
Notice: This community forum is not an official Poly support resource, thus responses from Poly employees, partners, and customers alike are best-effort in attempts to share learned knowledge. If you need immediate and/or official assistance please open a service ticket through your proper support channels.
Please also ensure you always check the VoIP , Video Endpoint , Skype for Business , PSTN or RPM FAQ's
