Yesterday, Microsoft made Windows 10 Insider Preview build 16296 available for download in ISO form. If you’ve been following along, you know that this is not the final version of Windows 10 version 1709, or the Fall Creators Update. But it is a near-final build.

So why would Microsoft issue this build now? It’s hard to say.

Microsoft first issued Windows 10 Insider Preview build 16296 to the Fast ring on September 22, almost two weeks ago. It included a number of important fixes but no new features, as you would expect given the timing.

Since then, Microsoft released Windows 10 Insider Preview build 16299 to the Fast ring on September 27, and then a minor bump, 16299.15, yesterday, on October 3. This, and the release of the original 16299 build, lead me to believe that Windows 10 version 1709 is essentially done.

So, again, why release a previous build in ISO form now? It’s unclear. In the past, Microsoft used to issue builds in ISO when those builds shipped to the Slow ring. But with 16299 now in the Slow ring, the availability of 16296 makes no sense. No sense at all.

Anyway, given where we’re at, it’s only a matter of time before the “final” version of Windows 10 version 1709—build 16299.something—is available to one and all in ISO form. But build 16296 is there if you want it. For some reason.