The Office 365 Admin Universal App has reached general availability.
If you have been running the beta version (Office 365 Admin Universal Beta) you need to install the released version.
If you have been running the ‘old’ version of the Office 365 Admin app on Windows 10, the app will be updated - if not, check the app store to ensure you have enable automatic updates or to manually check for update.
If you are using Windows Phone 8.1, the app will continue to run but will not receive any further update.