MC1134737 – (Updated) Microsoft Teams: Private channels increased limits and transition to group compliance

Product:

eDiscovery, Microsoft 365 admin center, Purview, Purview Communication Compliance, Purview compliance portal, Purview Data Loss Prevention, Teams

Platform:

Online, World tenant

Status:

Change type:

Admin impact, New feature, Updated message, User impact

Links:

Details:

Summary:
Microsoft Teams is updating private channels by increasing limits to 1000 channels per team and 5000 members per channel, enabling meeting scheduling, and shifting compliance policies from user mailboxes to team group mailboxes. Migration runs from October 2025 to January 2026; admins must update compliance policies before then.

Details:
Updated January 12, 2026: We have updated the content. Thank you for your patience.
In response to customer feedback, we are introducing enhanced flexibility, greater scalability, and streamlined compliance management for private channels in Microsoft Teams.
Note: It is important for compliance managers to review and take appropriate action before migration starts for these changes to private channels.
[What's changing?]
Private channels will transition use a channel mailbox instead of individual user mailboxes.
Organizations with compliance policies (retention, legal hold, data loss prevention, or eDiscovery) for private channels must review these policies and must apply policies to the Microsoft 365 group for the channel's team before migration begins to ensure continuity of the policy for a private channel. Existing policies will continue to apply to user mailboxes; post-migration, new data will be governed by policies on the group. Note that policies applied to the team's group can apply to all channels in the team.
After the transition to updated private channels in your organization, private channels will be updated as follows.
Private channels are no longer limited to 30 per team. Instead, private channels can be added up to the limit of 1000 total channels per team.
Private channels can now have up to 5000 members, instead of 250.
Meetings can now be scheduled in private channels.
Compliance policies for private channels are part of the team's group policies instead of the individual user level.
The migration of private channels to the updated capabilities will begin in early October 2025 and continue through January 2026 (previously December 2025). During this period, private channels will continue to operate normally. Admins and compliance managers should complete any required policy changes by October 2025 (previosly September), before the migration begins. Changes to private channel limits and meeting scheduling will follow in February 2026. Migration can start or end at different times for each tenant during the rollout period. To track progress, a new PowerShell command will be available for tenants to check whether their migration has started or is completed. This post will be updated soon with details on the PowerShell command.
As part of this change, newly created private channels will not be created with a document library by default; the root folder is used as a default location for any new files.
[When this will happen:]
General Availability (Worldwide): We will begin rolling out private channel migration early October 2025 (previously late September) and expect to complete by late January 2026 (previously mid-December 2025). Updated channel limits and meeting scheduling will begin rollout in early February 2026 and we expect to complete by end of February 2026.
[Action required by compliance managers and admins]
Purview eDiscovery and Legal Hold
With this change, private channel data will move from user mailboxes to the group mailbox, aligning with how shared channels data is stored. Previously, legal holds were applied to user mailboxes since private channel data resided in each member's mailbox. Post-migration, the latest version of private channel message data from each user's mailbox is moved to the private channel's group mailbox. Message edits and deleted messages will not be copied into the group mailbox.
Note: For users on hold, copies of message edits and deleted messages will remain in the user's preserved library folder until the hold expires, while the latest version of private channel message data from each user's mailbox is copied to the private channel's group mailbox.
Before migration
If a legal hold exists for a private channel, admins must also apply the policy to the team's group, in addition to the policy already applied to users' mailboxes, in order for a hold to apply to new data generated and stored in the private channel's mailbox. Note that policies applied to the team's group can apply to all channels in the team.

Screenshot 1: Setting up a new hold in Microsoft Purview compliance portal.
After migration
For existing holds admins will need to ensure that the hold is applied to the user mailbox as well as the new group mailbox, in order for a hold to apply to existing and new message data. Any new legal holds will need to be applied to the group.
For complete eDiscovery, include both the private channel's users' mailboxes and the team's group mailbox to retrieve pre-migration messages, message history, and post-migration new content.

Screenshot 2: Configuring an eDiscovery search in Microsoft Purview compliance portal.
Purview Data Loss Prevention (DLP)
With this change, private channel messages will be included as a part of the DLP policy scoped to the private channel's team's group, as opposed to the user mailbox.
Before migration
Admins must modify the "Teams chat and channel messages" policy for private channels to add the team's group containing the private channel, in addition to the user mailbox, in order to include new private channel messages in a policy. Note that policies applied to the team's group can apply to all channels in the team.
After migration
Ensure that "Teams chat and channel messages" policy for private channels is scoped to the team's group containing the private channel.

Screenshot 3: Configuring a data loss prevention policy in Microsoft Purview compliance portal.
Purview Retention Policy
After this change, creation of new private channel-specific policies will not be possible in the Purview portal. Instead, "Teams channel messages" policies applied to the team's group will now include private channels. Existing private channel policies will remain in effect and preserve all held message data in user mailboxes. Editing of existing policies will not be supported but policies can be removed.
Before migration
Apply current private channel retention policies (previously on user mailboxes) to Teams channel messages to include the team's group, in order to include new private channel messages in a policy. In Microsoft Purview compliance portal, go to solutions > Data Lifecycle Management > Retention policies. Note that policies applied to the team's group can apply to all channels in the team.
After migration
If the parent team's group retention policy differs from the private channel's policy, create a new or equivalent policy to ensure consistent retention.

Screenshot 4: Configuring "Teams channel messages" for a retention policy in Microsoft Purview compliance portal.


4. Microsoft policies for Optical Character Recognition
Before Migration:
In Microsoft Purview compliance portal, go to Settings, -> Optical character recognition (OCR), -> Select locations and scope to [1] all users and groups or [2] specific users and groups
After Migration:
Set the settings for "all users and groups" to cover private channels as specific users and groups are not supported.

Frequently asked questions
How can admins identify a user's private channel memberships?
Use Teams Admin Center under team settings, or run PowerShell: Get-TeamChannelUser to list members.
When is compliance manager action required?
If a policy (legal hold, eDiscovery, retention, DLP) applied to a user's mailbox, in order to include private channel messages, differs from the team policies for the team hosting the private channel. Policies must be applied to the team's group in order to include new private channel messages in a policy. Note that policies applied to the team's group can apply to all channels in the team.
During eDiscovery for users on hold or during migration, search both user mailbox and group mailbox for complete data on a private channel.
What if no action is taken?
User-level policies will not apply to a private channel's new message data. Team-level policies will apply to private channels.
Why isn't Microsoft automatically applying policies from user mailboxes to a private channel's team?
Tenant admins and compliance managers must assess and apply policies as needed. Group policies apply to all channels in the Team. Some user mailbox policies are intended for all of a user's messages, and some are intended for private channel messages. Each organization must review and decide on policies.
Is there any impact to end users?
During migration, users may see duplicate search results in Teams searches-both links will navigate to the same content in Microsoft Teams.
6. When will migration happen for my tenant and how long will it take?
Migration can start or end at different times for each tenant during the rollout period and can take some weeks depending of the tenant. To track progress, a new PowerShell command will be available for tenants to check whether their migration has started or is completed. The command will be -
Get-TenantPrivateChannelMigrationStatus -TenantId <tenantId>
Please refer to this blog post for more information: New enhancements in Private Channels in Microsoft Teams unlock their full potential
We appreciate your attention to this important update.
Please refer to this blog post for more information: New enhancements in Private Channels in Microsoft Teams unlock their full potential
We appreciate your attention to this important update.

Change Category:
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Scope:
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Release Phase:

Created:
2025-08-14

updated:
2026-01-13

Task Type

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Docu to Check

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MS Preperations

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summary for non-techies**

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Direct effects for Operations**

Compliance Policy Management
Failure to update compliance policies before migration may lead to loss of legal hold and retention capabilities for private channel messages, resulting in potential data loss.
   - roles: Compliance Manager, IT Administrator
   - references: https://techcommunity.microsoft.com/blog/microsoftteamsblog/unlocking-the-full-potential-of-private-channels-in-microsoft-teams/4438767

User Experience During Migration
Users may experience duplicate search results in Teams searches during migration, leading to confusion and inefficiency.
   - roles: End User, Team Member
   - references: https://techcommunity.microsoft.com/blog/microsoftteamsblog/unlocking-the-full-potential-of-private-channels-in-microsoft-teams/4438767

Data Loss Prevention (DLP)
If DLP policies are not updated to include the team's group mailbox, new private channel messages may not be protected, increasing the risk of data breaches.
   - roles: Compliance Manager, IT Administrator
   - references: https://techcommunity.microsoft.com/blog/microsoftteamsblog/unlocking-the-full-potential-of-private-channels-in-microsoft-teams/4438767

Retention Policy Management
Inadequate application of retention policies to the team's group may result in inconsistent data retention practices, risking compliance violations.
   - roles: Compliance Manager, IT Administrator
   - references: https://techcommunity.microsoft.com/blog/microsoftteamsblog/unlocking-the-full-potential-of-private-channels-in-microsoft-teams/4438767

User Access to Private Channels
Without proper management, users may face access issues to private channels due to misconfigured group policies, impacting collaboration.
   - roles: End User, Team Member
   - references: https://techcommunity.microsoft.com/blog/microsoftteamsblog/unlocking-the-full-potential-of-private-channels-in-microsoft-teams/4438767

Configutation Options**

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Opportunities**

Enhanced Compliance Management
Transitioning compliance policies from user mailboxes to team group mailboxes streamlines compliance management, allowing for more centralized and efficient policy application across private channels. This reduces the complexity of managing individual user policies and ensures consistency in compliance across the team.
   - next-steps: Review existing compliance policies and apply them to the team group mailboxes. Ensure that all compliance managers are trained on the new processes and tools for managing group-level compliance policies.
   - roles: Compliance Managers, IT Administrators
   - references: https://techcommunity.microsoft.com/blog/microsoftteamsblog/unlocking-the-full-potential-of-private-channels-in-microsoft-teams/4438767

Scalability of Private Channels
With the increase of private channels to 1000 per team and members to 5000 per channel, teams can now collaborate more effectively without the limitations previously imposed. This allows for larger projects and more extensive collaboration across departments.
   - next-steps: Assess current team structures and project needs to identify opportunities for utilizing the increased limits. Develop guidelines for managing larger teams and projects effectively within private channels.
   - roles: Project Managers, Team Leaders
   - references: https://techcommunity.microsoft.com/blog/microsoftteamsblog/unlocking-the-full-potential-of-private-channels-in-microsoft-teams/4438767

Improved User Experience with Meeting Scheduling
The ability to schedule meetings directly within private channels enhances user experience by integrating communication and collaboration tools. This reduces the need to switch between applications and improves workflow efficiency.
   - next-steps: Inform users about the new meeting scheduling feature and provide training on how to effectively use it within private channels. Gather feedback to continually improve the user experience.
   - roles: End Users, Team Leaders
   - references: https://techcommunity.microsoft.com/blog/microsoftteamsblog/unlocking-the-full-potential-of-private-channels-in-microsoft-teams/4438767

Potentional Risks**

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Data Protection**

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IT Security**

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DPIA Draft**

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explanation for non-techies**

Microsoft Teams is making some changes to how private channels work, and these updates are set to roll out between October 2025 and January 2026. The main changes include increasing the number of private channels you can have in a team from 30 to 1000 and allowing up to 5000 members in each channel. This is like expanding a small meeting room into a large conference hall, giving more space for discussions and collaboration.

Another significant change is how compliance policies are managed. Previously, compliance settings like data retention and legal holds were tied to individual user mailboxes. Now, these will be managed at the team level, using the team's group mailbox. Think of it like moving from managing each person's desk individually to managing the entire office space. This shift means that any rules or policies need to be updated to apply to the team as a whole, rather than just individual users.

For those involved in compliance, it's important to update these policies before the migration starts in October 2025. If not updated, the old policies won't apply to new data created in private channels after the migration. It's like needing to update the office's security system to cover a new wing of the building; if you don't, that new area won't be protected.

Additionally, meetings can now be scheduled directly within private channels, which is a new feature that enhances collaboration. It's like being able to book a meeting room directly from your team's chat, making it easier to coordinate and plan discussions.

During the migration period, everything will continue to work as usual, but it's crucial for compliance managers and admins to make the necessary policy changes to ensure a smooth transition. After the migration, any new legal holds or data policies will need to be applied at the team level, rather than the individual level.

For those managing compliance, this means checking and possibly adjusting your current settings to make sure they align with the new team-based approach. This might involve using tools like PowerShell to track the migration's progress and ensure everything is set up correctly.

Overall, these changes are designed to make managing private channels more scalable and efficient, much like upgrading from a small car to a larger vehicle that can carry more passengers and cargo.