- Microsoft has released Windows 11 26H2 evaluation ISOs, giving businesses a 90-day trial to test the upcoming feature update.
- The ISO is based on build 26300.9457, which includes the KB5129195 out-of-band update.
- The release indicates Windows 11 26H2 is nearing general availability, following its arrival in the Release Preview channel.
- Windows 11 26H2 will use an enablement package, similar to 25H2, rather than requiring a full operating system upgrade.
Microsoft has published the evaluation ISOs for Windows 11 26H2, giving network administrators a 90-day, no-activation way to test the upcoming feature update before general availability.
The arrival of evaluation media is more significant than it might sound. Microsoft uses these images so businesses can test a new operating system release against their apps, hardware, management tools, and deployment processes before rolling it out broadly.
For regular users, the timing is also a useful signal. Windows 11 26H2 has already reached the Release Preview channel, and the availability of evaluation ISOs suggests that the company is moving through the final stages before the public release.
The evaluation images are based on the KB5129195 out-of-band update (build 26300.9457).
Microsoft is preparing Windows 11 26H2 for deployment
Windows 11 26H2 follows the same general servicing approach Microsoft used for version 25H2. Instead of delivering a completely separate operating system installation, the company enables the new features through enablement package KB5121794.
In other words, the enablement package essentially acts as a switch that activates functionality already staged in the underlying Windows installation.
What the evaluation ISO actually does
The evaluation ISO targets organizations and network administrators, not personal installations. Microsoft provides it as a 90-day trial with no activation required.
The image currently available for download from the Microsoft servers:
26300.9457.260913-1737.26h2_ge_release_svc_refresh_CLIENTENTERPRISEEVAL_OEMRET_x64FRE_en-us.iso
It gives administrators a practical way to build test and virtual machines around the version that Microsoft is preparing to release.
Although the ISOs are meant for organizations, they’re still interesting for enthusiasts. It also indicates that 26H2 is getting closer to its final release.
Pureinfotech’s Take
I’m not surprised to see the evaluation ISOs showing up now. At this point, Windows 11 26H2 feels like Microsoft is getting the last pieces in place before the public rollout.
I also wouldn’t bother installing the evaluation ISO on a regular home computer. If you just want to see what 26H2 has to offer, the Release Preview build makes far more sense.
For me, the more interesting part is how little actually changes when upgrading to 26H2. Microsoft is treating this much like 25H2, using the enablement package to turn on features already in the Windows 11 installation. So despite the new version number, this isn’t the kind of upgrade that should require a major reinstall or overhaul.
I’ll be watching the final rollout closely because the interesting part now is what Microsoft enables by default when 26H2 reaches everyone.
What are your thoughts about Windows 11 26H2? Let me know in the comments.
Mauro Huculak is a Windows How-To Expert and founder of Pureinfotech in 2010. With over 23 years as a technology writer and IT Specialist, Mauro specializes in Windows, software, and cross-platform systems such as Linux, Android, and macOS.
Certifications: Microsoft Certified Solutions Associate (MCSA), Cisco Certified Network Professional (CCNP), VMware Certified Professional (VCP), and CompTIA A+ and Network+.
Mauro is a recognized Microsoft MVP and has also been a long-time contributor to Windows Central.
You can follow him on YouTube, Threads, BlueSky, X (Twitter), LinkedIn and About.me. Email him at [email protected].
