Summary
Apple stopped approving apps that use VOIP push notifications for non-VOIP purposes starting in June 30, 2020. A new update enables the Microsoft Skype for Business for iOS mobile client to support push notifications for iOS 13.
How to get this update
To get this update, install the November 2020 cumulative update 6.0.9319.598 for Skype for Business Server 2015, Web Components Server and the November 2020 cumulative update 6.0.9319.598 for Skype for Business Server 2015, Core Components.
