Microsoft Teams strengthens messaging security by default in January

Microsoft will begin automatically enabling Teams messaging safety features by default on January 12, 2026 for tenants that haven’t customized their settings, activating weaponizable file type blocking, malicious URL detection, and false-positive reporting. Organizations with customized configurations will see no change, but administrators are urged to review and adjust settings before the deadline and update internal documentation. The move is part of broader Microsoft security enhancements responding to increased cyber risks targeting Teams, including protections against phishing, malware, and suspicious external traffic.