Microsoft Teams Private Channel and Compliance Changes

Microsoft announced major changes to private channels in Microsoft Teams on the official Teams blog and in Microsoft 365’s Message Center Notification MC1134737 of which you should know.

What are the upcoming changes?

The limit or private channels within a Team will be increased from 30 to 1000.
The limit from 250 users per private channel will be increased to 5000.
Channel meetings will be available in private channels.
Transition to Microsoft 365 group-based storage for private channels
Transition from individual to channel based mailbox.
Compliance policies (e.g. DLP, retention, …) for private channels will be the same ones as for the Microsoft 365 group instead of individual user level ones.

What is the timeline for the change?

Migration will probably start in late September 2025 and finish by December 2025, with private channel data moving to the team’s group mailbox. Private channels will remain functional during this time, and a special migration is planned for early 2026.

What actions are required?

Compliance administrators handling e.g. retention, legal hold, DLP, and eDiscovery in Microsoft 365 must adjust scopes to ensure compliance policies cover Microsoft 365 groups, including private channels, before migration starts, by September 20, 2025. Existing policies for user mailboxes will stay in effect; after migration, new private channel data will follow Microsoft 365 group mailbox policies.

Conclusion, opinion and summary

In my view, the alignment of private channels with Microsoft 365 groups concerning compliance represents a positive advancement, as it further standardizes compliance management and reduces the number of “special” configurations associated with private channels that require attention.

On the other hand, the ability to create up to 1,000 private channels may pose challenges in terms of user engagement. With more than 10 channels within a team in Microsoft Teams, the environment can quickly become confusing and overwhelming for users. I would advocate for the creation of multiple smaller teams rather than fewer, larger teams, as this approach simplifies navigation and management. In my view, an increase in the number of channels correlates with heightened complexity for both users and team owners. Users may inadvertently overlook important information due to the sheer volume of updates and communications they must process daily. Consequently, the integration of AI, such as Microsoft 365 Copilot, will be essential for users to stay informed and address any missed information.

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