Microsoft is enabling default messaging safety protections in Teams to reduce exposure to malicious content and strengthen collaboration security.
This change applies to tenants still using the default messaging safety configuration introduced in September 2025.
Timeline
The rollout starts on 12 January 2026.
Impact for your organization
Microsoft introduced three new security features for Teams chats and channel conversations in September, as a Public Preview. These features are turned off by default during the Preview phase. Microsoft has stated they will be enabled when the features reach General Availability (GA).
The Preview phase ends in January 2026.
As a result, the following three security features will be enabled on or after 12 January 2026, unless a Teams admin has manually modified the Teams configuration.
- Weaponizable file type protection, licensing requirements are still undocumented. Protection is enforced if at least one participant has the feature enabled.
- Malicious URL protection, included with a Teams license as part of base protection. Protection is enforced if at least one participant has the feature enabled.
- Report incorrect security detections, Defender for Office 365 Plan 2 is required, as this feature follows the same requirements as reporting a security concern, which was introduced in June 2023.
