1. Which Outlook clients are supported?

We support the following Outlook clients, provided they are connected to Exchange Online (Microsoft 365):

• Outlook for Web (OWA)

• New Outlook for Microsoft 365

• Classic Outlook for Microsoft 365 (e.g., “Microsoft Outlook for Microsoft 365 MSO”)

• Outlook 2021 Bulk Billed

• Outlook 2024 Bulk Billed

• Retail/Personal Outlook (Microsoft 365 consumer versions)

These clients are compatible because they support IdentityAPI 1.3 or higher, as outlined in Microsoft’s Outlook API requirement sets documentation.

2. Which Outlook clients or environments are not supported?

Any client connected to on-premises Exchange Server, even in hybrid configurations, on-prem Exchange REST API support has been deprecated.

Older Outlook clients that do not support IdentityAPI 1.3. e.g. Outlook 2016 and 2019 Bulk Billed.

3. Why is Exchange Online required?

Microsoft Graph Mail API, which we rely on, is only available in Exchange Online.