M365 Changelog: Teams Support of Internal Guest User (formerly known as State 3 and State 4 accounts)

MC291316 – Teams is adding support for Azure AD’s internal guest users (users whose UserType value is “guest” with credentials managed by the host organization either on-prem or in the cloud). These internal user would sign-into Teams like any other users and would be able to collaborate with other users in the host organization.

Note: This change is to support legacy scenarios (formerly known as guest user state 3 and 4), that may have blocked organizations from utilizing internal guest access previously. This change does not impact existing guest access settings.

This message is associated with Microsoft 365 Roadmap ID 87830

When this will happen:

Microsoft will roll out this change beginning in mid-October and should be complete by the end of November.

How this will affect your organization:

Microsoft will roll out this change beginning in mid-October and should be complete by the end of November.

If your organization supports internal guest users, these users will now be able to sign into Teams as guests and collaborate with other users of the hosting organization.

What you need to do to prepare:

Notify internal guest users about the change, so they can now use Teams to collaborate with other users of the hosting org.

For information on  managing guest access, review: Guest access in Microsoft Teams