MicrosoftMicrosoftHmerckx What Adam is saying is that there is no need to 'validate anything' as the phone will not successfully authenticate if the app was not approved.
This is how it works:
Starting with the 5.9.4.3247 release the VVX can only authenticate to Skype for Business Online using the app model. Sign-in will simply not work unless the Poly app has been manually approved by an administrator for the tenant where the user account is homed that is attempting to sign-in to the phone.
Once the app has been approved in the tenant (which you have done) then all VVX phones running 5.9.4.3247 will successfully sign-in. They cannot use the older user authetnication method regardless of the app's status, so there is nothing to confirm in any logs. If a VVX running 5.9.4.3247 or newer succesfully signs-in, then it's using the new app model and will continue to work that way from that release though all future releases.
Regarding the firmware version issue, it is recommended to disable Device Updates in your Office 365 tenant for this reason:
http://blog.schertz.name/2016/07/device-updates-with-skype-for-business-online/
Microsoft typically does not update the published version for most minor updates, and when they are it historically takes a long time. I expect this version will be posted to the updates services at eventually though as it'll be required before long. But for now you'll want to disable the updates to prevent the phones from rolling back automatically.
