If your organization has deployed an on-premises Exchange Server infrastructure, the minimum requirement is to configure Azure Active Directory identity synchronization (which we'll discuss in Chapter 15, Planning Identity and Authentication for Teams) and ensure the users have Microsoft Teams and Exchange licenses enabled. For the best experience, you'll need to make sure your on-premises Exchange Server environment is at least Exchange Server 2016 with CU3 or later applied.

If you choose to configure retention policies that include Microsoft Teams, each on-premises user will require an Exchange Online license to be enabled as Teams will store the retention data in an Exchange Online shadow mailbox for the user.

If you choose to use the integrated meetings and calendaring features of Teams, you will need to configure Exchange Server hybrid. Configuring Exchange Server hybrid connectivity is outside the scope of the MS-300 exam.