Changing to the Outlook App is not mandatory, however, it's the only application that will support TU email. The free Outlook mobile app is available through your device's App store. See TU's Microsoft Office self-help resources.
This depends on the device and if it's internet ready or has a web browser. You can use the Office 365 Mail app or configure TU email using the native app.
Remember TU uses to enhance the security of NetIDs, so whether you use the app or the web, you will have to enroll your device to check your TU email.
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