Microsoft announces a major update for Teams users, aimed at improving communication security within companies. This new feature, integrated with Microsoft Defender for Office 365, will better counter external threats. Discover how these measures can transform the way companies protect their internal communications.
The 3 key points not to miss
- Microsoft introduces a feature to block external users on Teams, available from January 2026.
- Administrators can manage up to 4,000 domains and 200 blocked email addresses via Microsoft Defender.
- This update aims to counter cyberattacks, with alerts for suspicious actions and automatic protections against threats.
External user blocking features
Starting in January 2026, companies using Microsoft Teams will be able to prevent external users from sending messages, making calls, or sending meeting invitations. This blocking option, accessible via the Microsoft Defender for Office 365 admin center, offers administrators a new layer of control over their organization’s communications.
To activate this feature, administrators will first need to adjust some default options in the Teams admin center. Once these settings are made, they can manage blocked external users and domains directly from Microsoft Defender.
Protection against cyberattacks
This Microsoft initiative responds to increased use of Teams by cybercriminals. They exploit the platform to launch social engineering attacks targeting employees. In addition to blocking options, Microsoft will introduce automatic alerts for suspicious actions from external domains.
Furthermore, starting in January, Teams will automatically integrate protections against malicious URLs and dangerous file types. These features aim to enhance company security against increasingly sophisticated threats.
Deployment schedule
The deployment of these new security options will begin in early January 2026 and is expected to be completed by mid-January. Organizations already using Teams in combination with Microsoft Defender for Office 365 will have access to these enhanced features at no additional cost.
The history of Microsoft Teams
Launched in 2017, Microsoft Teams quickly established itself as an essential tool for business collaboration. Designed to facilitate communication and collaboration, Teams integrates features such as instant messaging, video calls, and file sharing. With the rise of remote work, the platform has seen its use skyrocket, becoming an essential pillar for many organizations worldwide.
Microsoft has continuously evolved Teams to meet the changing needs of its users. Regular updates and new features, such as enhanced security options, illustrate the company’s commitment to providing a secure and reliable platform for professional collaboration.
