Development on the next feature update for Windows 10, codenamed Redstone 4 and often referred to as the Spring Creators Update, is now complete. According to our sources, on Friday Microsoft internally signed-off on the final build of Redstone 4 at build 17133, making said build the one that will be released to manufacturers (RTM) for pre-loading onto new devices.

Assuming there are no catastrophic issues that arise when testing build 17133, this is the production build that Microsoft will service with security and cumulative updates throughout the lifespan of the Spring Creators Update, just like it has with previous releases of Windows 10. Build 17133 is expected to hit Fast ring this week, followed by Slow ring not long after. Of course, since this is the RTM build, it will also make its way to the Release Preview ring too. So, for Insiders in the Release Preview ring, prepare for a big update within the next week or so.

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Now that Redstone 4 has been signed off, Microsoft will now turn its efforts to squashing any last minute bugs or issues via patches that will be flighted to Insiders in the days up until release. These patches will then be released as one big day-zero cumulative update, which will likely rollout to the public alongside the official release of the Spring Creators Update. On that subject, we're hearing Microsoft will begin rolling out the Spring Creators Update sometime in April, likely April 10, to an initial subset of devices before rolling out more broadly, just like in the past.

Microsoft will want as many Insiders as possible testing the RTM build of the Spring Creators Update, before moving on to Redstone 5. Insiders in the Skip Ahead are already testing early Redstone 5 builds with Sets enabled, while the rest of the Insider Program is testing Redstone 4. In the next couple of weeks, Microsoft will begin flighting Redstone 5 to Insiders in the Fast ring as well, so be sure to drop to a slower ring once 17133 is released to avoid being upgraded to pre-release Redstone 5 builds.

Will you be upgrading to the Spring Creators Update once it becomes available? Let us know in the comments!