On 5th December Microsoft put out a major update notice (MC228482) for Microsoft Teams. Beginning on February 8th, 2021 (just over 2 months from the announcement), Microsoft is turning on Guest access in Microsoft Teams by default for any organisations who have not explicitly disabled guest access.
Currently, the service default is guest access off, but if you want Guest access for Microsoft Teams to remain disabled for your organization, you will need to set/confirm that the Guest access setting is set to “Off” instead of “Service default“.
If you already have guest access turned on, no action is required.
From 8th February 2021, Service default will switch to Guest Access On. If you manually set this to On or Off you will not be impacted by the service default change.
You can change this under Org-wide settings / Guest Access in the Teams Admin Center (Guest access – Microsoft Teams admin center)
This setting relates to the guest access setting for Microsoft Teams as one service in the wider Office / Microsoft 365 Services. Ultimately, if and how guest access will work for Microsoft Teams depends on settings in the following services:
- Azure Active Directory: Guest access in Microsoft Teams relies on the Azure AD business-to-business (B2B) platform. This authorization level controls the guest experience at the directory, tenant, and application level.
Azure AD determines whether external collaborators can be invited into your tenant as guests, and in what ways.
- Microsoft Teams: Controls the guest experience in Microsoft Teams only.
- Microsoft 365 Groups: Controls the guest experience in Microsoft 365 Groups and Microsoft Teams.
- SharePoint Online and OneDrive for Business: Controls the guest experience in SharePoint Online, OneDrive for Business, Microsoft 365 Groups, and Microsoft Teams.
For more detail check out this blog: Controlling Microsoft Teams Guest Access on a per-team basis#
If you have guest access disabled at the Azure Active Directory level, this service default change will not open up guest access for Microsoft Teams, since sharing in Microsoft 365 is governed at its highest level by the organizational relationships settings in Azure Active Directory.