Microsoft Brings CLAT Support to Windows 11, Making IPv4 Apps Work on IPv6 Networks

Microsoft has announced that Windows CLAT (Customer-side Translator) is now generally available in Windows 11, allowing IPv4-only applications to work on IPv6-only and IPv6-mostly networks.

According to Microsoft’s announcement, the feature arrived with Windows 11 Build 26200.9550, which the company released as a preview update last month.

The feature targets organizations moving to IPv6 infrastructure that still rely on older applications and services requiring IPv4 connectivity.

Windows CLAT allows IPv4 applications to run on IPv6 networks

Windows CLAT uses the 464XLAT translation mechanism to help IPv4 applications communicate across IPv6 networks without requiring developers to modify their software.

The system relies on two components. CLAT translates IPv4 traffic into IPv6 directly on the Windows device, while PLAT handles the translation back to IPv4 on the provider’s network.

This approach allows organizations to gradually move toward IPv6-only networks while maintaining support for existing applications.

Microsoft says the technology can also simplify network management, reduce infrastructure costs, and limit potential security risks associated with maintaining separate IPv4 and IPv6 environments.

Windows CLAT supports Wi-Fi, Ethernet, and cellular connections

Windows CLAT works across Wi-Fi, Ethernet, and cellular interfaces, making it suitable for different types of Windows 11 devices and network environments.

The feature can automatically discover its configuration when native IPv4 connectivity is unavailable, reducing the need for manual setup.

This should make IPv6 adoption easier for businesses that want to modernize their networks without disrupting software that still depends on IPv4.

Windows CLAT is now generally available

After approximately a year of private and public preview testing, Microsoft has made Windows CLAT generally available in Windows 11.

The release gives organizations another way to reduce their dependence on IPv4 infrastructure without immediately replacing legacy applications.

In other news, Microsoft warns IT admins to migrate Defender APIs before February 2027, while the company has also released Windows 11 KB5134133 and KB5134134 emergency updates.