I can make the update to 5.11 and everything is sucessfull. But after the Phone reboots it reverts to 4.3
Toyuwa
welcome to the Polycom Community.
Did you want to post in the LYNC / Skype for Business section and if yes how did you upgrade the phone?
The Cab File upgrade was only added in UC Software 5.0.0 so I cannot imagine this being the case. In addition there is no software 4.3 as we have 4.0.x and 4.1.x and then went to 5.x.x
Please provide more details and correct firmware versions.
Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.
Best Regards
Steffen Baier
Polycom Global Services
If official support is required please check how to phone or open a case here
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