Starting with July 2019 cumulative update, Microsoft Skype for Business Server 2019 supports the feature of sending custom client policy entries to the UCWA clients, such as Skype for Business on Mac, Skype for Business on Android, and Skype for Business on iOS. The custom policies entries can be configured through the New-CsClientPolicyEntry cmdlet. The new feature is meant to provide a more consistent client experience on all platforms.
Note The support for a specific custom client policy entry must exist in the UCWA client before the setting can go into effect.