End-to-end encryption for one-to-one Microsoft Teams calls now Generally Available

This feature is really awsome!
But "once the update is received" means obviously that our organisation has not received the update yet. We used these support-docs:
https://docs.microsoft.com/en-us/MicrosoftTeams/teams-powershell-install
and

https://docs.microsoft.com/en-us/microsoftteams/teams-end-to-end-encryption
and this
https://microsoft365pro.co.uk/2021/12/04/teams-real-simple-with-pictures-lets-deploy-end-to-end-encryption-e2ee-for-1-to-1-voip-calls/ 

After we installed all the needed powershell-extensions none of the appropriate commands did work. Even  
Get-CsTeamsEnhancedEncryptionPolicy did not show anything else than the same error-message like all the other commands:

The argument "commandInfo" is NULL.
+ Get-CsTeamsEnhancedEncryptionPolicy -Identity Global
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidArgument: (:) [Get-CsTeamsEnhancedEncryptionPolicy], PSArgumentNullException
+ FullyQualifiedErrorId : ArgumentNull,Microsoft.Teams.ConfigApi.Cmdlets.GetCsTeamsEnhancedEncryptionPolicy

After we switched our teams to the public preview inside the admin-web-backend these commands worked as expected. But even if we use the public preview version (and also the developer preview) the clients do not show up the switch for using E2EE. This is even more suspicious, because it is the newest version installed (1.4.00.32771) on all clients, but SOME have the switch. The most of them do not show it in the settings/privacy tab:

Is there a possibility to find out, when our tenant will receive the update here (we are german school) without polling every day by getting error messages or missing E2EE Switch or do we did some mistake?

Thanks in advance
Bernd