Note the addition of a new policy for Exchange Online to block ActiveSync clients. To protect email, the following diagram illustrates which policies to update from the common identity and device access policies. For more information, see Outlook for iOS and Android FAQ.

These mobile Outlook apps are also architected with security capabilities that support mobile use and work together with other Microsoft cloud security capabilities. Outlook for iOS and Android provide support for the best features of Office 365. These recommendations require your users to use modern email clients, including Outlook for iOS and Android on mobile devices. You can learn more about these security tiers, and the recommended client operating systems, referenced by these recommendations in the recommended security policies and configurations introduction. These recommendations are based on three different tiers of security and protection that can be applied based on the granularity of your needs: starting point, enterprise, and specialized security. This guidance builds on the Common identity and device access policies and also includes a few additional recommendations. This article describes how to implement the recommended Zero Trust identity and device access policies to protect organizational email and email clients that support modern authentication and conditional access.

Microsoft secure email login