Ask @WinObs – What is 19H1 And Why Should I Know About It?

Richard Hay

Here’s why you’ll be seeing 19H1 mentioned a lot: Microsoft confirmed that 19H1 is a new code name for the seventh feature update for Windows 10.

Microsoft is a big fan of code names and they have been using them for years on various software/hardware projects. A code name helps, well at least sometimes it does, to keep the identity of a new product under wraps while it is being worked on internally at the Redmond company.

You might even remember some of them from over the years:

  • Windows 3.1: Janus
  • Windows 95: Chicago
  • Windows 98: Memphis
  • Windows ME: Millennium
  • Windows 10 RTM and November Update: Threshold (TH1 & TH2)
  • Windows 10 Anniversary Update, Creators Update, Fall Creators Update and April 2018 Update: Redstone (RS1, RS2, RS3, & RS4)

Of course, the sixth update as already mentioned will be Redstone 5 (RS5). It is the final update to use the Redstone code name.

The new code name, 19H1, breaks down into two elements.

The 19 represents the year of the update’s release – in this case, 2019. The H1 indicates the update was released in the first half of that year. Although that makes for a possible 6-month window the update could be released in, I am not expecting Microsoft to vary from their current update completion targets of March and September each year.

That means future updates should follow a pattern of 19H2, 20H1, 20H2 and so on.

Now, when we hear or read about a code name for one of the Windows 10 feature updates we can get a general idea of when that update was made available. The generic code names like Threshold and Redstone never had the ability to communicate the release’s time frame, and neither did feature update names like Creators Update or Fall Creators Update.

However, Microsoft now seems to be using more date-connected names like April 2018 Update, and current rumors indicate the next feature update will be called the October 2018 Update. For users worldwide, who live in different hemispheres and experience different seasons, this prevents confusion around names like the Fall Creators Update.

The value in understanding these code names and related changes is it helps you keep track of what Microsoft is doing when it comes to Windows 10. The vast majority of you here at Windows Secrets are advanced users and I suspect many of you are also testing pre-release builds of these Windows 10 feature updates.

So, let’s spend a minute and cover where Microsoft is in the current development process as the company released two new pre-release builds for Windows 10 feature updates.

Redstone 5 (RS5)

Build 17723 is the 20th public build release in the Windows Insider Program, and it’s a preview of the upcoming sixth feature update for Windows 10.

Microsoft recently announced that the development process is moving towards stabilizing the updates code for release later this year. That means we will likely not see any significant feature changes and only minor tweaks to existing elements in the update.


Build 18204 is the first release in the public development of the seventh overall feature update for Windows 10. As the 19H1 codename indicates, this update is expected in the first half of 2019.

At this early stage of development, we do not know what types of big-ticket features Microsoft might be looking at for this release.

(I suspect the on again/off again Sets feature could return in development builds as the company looks to take another shot at getting that ready for general release. They previously attempted to test this in Redstone 4 and Redstone 5 but decided to not continue public development to keep working on it internally. The feature, which allows you to have one app window with multiple associated tabs with different apps open, was very rough around the edges and certainly was not ready for prime time.)

We can certainly expect Microsoft to continue the process of modernizing the legacy Control Panel and moving those options into the Windows Settings app as they have been over the last three years. I think it is great that they have not rushed this process as the Control Panel is an intricate element of the operating system. Moving things haphazardly would only create chaos.

Other areas they will likely continue work on include security and accessibility which they have addressed in nearly every feature update for Windows 10.

One confirmed item Microsoft is addressing in both the RS5 and 19H1 build releases is an effort to improve your Windows Update experience. Over the last few feature updates, Microsoft has sped up this process, so you are offline without your computer for only a short period of time.

However, this new change in RS5 and 19H1 is going to use a predictive AI model to verify when you are not using your device, then use that pattern of behavior to find a convenient time to apply an update. In addition, this same AI model will work to predict that you have just walked away from your device for a brief period and not restart to install the update during that time frame.

This predictive model will be trained and updated on a regular basis to improve its interpretation of when the system is free to install an update. I could also see this being used to predict the best time to apply an update based on your usage patterns as well as to prevent any disruption to your workflow. If you hit a snag in this process and it updates when you were not expecting it to, just send them something in the Feedback Hub so they can use that data to further train their AI model.

Something tells me this will be a very popular addition to the operating system based on how many users get hit with these unexpected and disruptive update cycles while they are working and need their devices.

Want to get involved with all of this? If you are not a Windows Insider, it is easy enough to join by visiting and signing up with your Microsoft Account.

= Paid content

All Windows Secrets articles posted on 2018-07-31:

Richard Hay

About Richard Hay

Richard, a 30-year Navy veteran, has been watching and writing about tech for over two decades. He is a Microsoft MVP and senior contributing editor at Penton's SuperSite for Windows.