Over the last 4 1/2 years, Microsoft has been steadily releasing testing builds of Windows 10 as it moved through various milestone feature updates.

Those of you whom have been around since those early days of the Windows Insiders Program know those names by heart:

November Update, Anniversary Update, Creators Update, Fall Creators Update, April 2018 Update, October 2018 Update, May 2019 Update, and most recently the November 2019 Update.

Each of them also had a code name as they were in active development: Threshold 1, Threshold 2, Redstone 1, Redstone 2, Redstone 3, Redstone 4, Redstone 5 and more recently code names that reflected the time of year the updates were being made available – 19H1, 19H2, and 20H1.

Well today, with the release of Windows 10 Build 19536 to the Windows Insider Fast Ring, a shuffle in the testing process is happening that will give Windows Insiders near bleeding edge access to early builds of Windows 10 as it is in active development.

Insiders are familiar with the ringed approach to testing pre-release builds of Windows 10. There are four in total and in order of stability/early access to features and updates they are:

• Release Preview Ring (app, driver, and firmware updates)
• Slow Ring (fairly stable builds)
• Fast Ring (potentially less stable builds)
• Skip Ahead Ring (Deprecated)

In the past, the next upcoming feature update has been in the Fast and Slow Ring at a varying release pace based on stability and how close that next feature update was to its intended release for general availability.

Over the last few weeks, builds of Windows 10 (20H1) has been released in both the Fast and Slow Rings at the same time. This update for Windows 10 is expected sometime in the first six months of 2020 – thus the 20H1 code name.

The release of Windows 10 Build 19536 today into the Fast Ring is where the shuffle occurs in Microsoft’s testing approach.

Build 19536 is from the RS_PRERELEASE branch and is some of the latest code being build by the Windows software engineers. As Brandon LeBlanc put it in the release notes for Build 19536, this is bleeding edge updates for Windows 10 as it is being developed:

Internally, our engineers work in development cycles with various milestones. The active development branch (called “RS_PRERELEASE”) is where the teams check in all their latest code changes into the OS. Moving forward, the Fast ring will receive builds directly from this active development branch and new features will show up in these builds first.

Officially these new fast Ring builds will not be known by any specific code name but unofficially, I am calling these releases Windows 10 vNext.

The plan appears to be to split off of this branch when the code is ready for its final development steps leading up to a public release/general availability. I suspect that branch will then head into the Slow Ring and be known under its code name such as 20H2, 21H1, 21H2, etc.

In the meantime, Windows 10 vNext will continue to get new builds in Fast Ring. These builds will see new features and enhancements at very early stages but without any commitment or designation for these updates to be targeting a specific feature update. As LeBlanc put it in the release notes for 19536:

New features and OS improvements done in this branch during these development cycles will show up in future Windows 10 releases when they are ready. And we may deliver these new features and OS improvements as full OS build updates or servicing releases.

What does all of this mean for Windows Insiders?

Well, if you want bleeding edge and early access to new features – then put your device into the Fast Ring and hang on tight. Be aware though, bleeding edge means potential for more bugs and other issues relating to performance and operating system failures. Make an informed choice to get these very early stage updates for Windows 10.

Now, if you prefer stability then the Slow Ring is going to be your likely best choice. I suspect this is where upcoming feature updates and servicing releases will spend a lot of time getting stabilization and bug fixes ahead of their official availability. Short of the Release Preview Ring, this is the safest place to test new builds if you do not have the desire to possibly have your system unstable.

Once a new feature update or servicing release is pushed to the public from Slow Ring, I would expect to see the next update be split out of the Windows 10 vNext Fast Ring with the cycle starting all over at that point.

All the while, Windows 10 vNext in the Fast Ring will continue to receive updates that give Insiders early access to new goodies in Windows 10. Just keep in mind – there are zero commitments that anything you see in Windows 10 vNext will eventually make it into the Slow Ring and/or a final release.

Windows 10 vNext is a pure testing ground for new ideas and concepts – the key word is testing.

Enjoy but make good ring choices!