Microsoft is rolling out to Windows Insider testers in the Slow Ring its second test build of Windows 10 19H2, AKA 1909. Today's build includes fixes plus a handful of new features. The fixes can be applied immediately, but the new features are all turned off by default at the moment so that it can test the off-by-default technology it will use when it delivers this feature update to mainstream users this fall.
Today's 19H2 test build, No. 18362.10005, adds a change enabling third-party digital assistants like Amazon's Alexa, to voice-activate above the Lock screen. It also includes a key-rolling or key-rotation feature that allows secure rolling of recovery passwords on MDM-managed Azure Active Directory devices in certain circumstances to help prevent accidental recovery-password disclosure. And it includes an update to keep Windows containers from supporting mixed-version container pod scenarios since Windows containers require matched host and container versions.
However, as of right now, all of these new features are off by default in this test build, just as they will be in the final version of Windows 10 19H2/1909. Microsoft officials said the plan is that the team "may ship features in these updates turned off by default and turn them on via controlled rollouts" in the name of getting better feedback on overall build quality. Microsoft plans to follow up today's build with another 19H2 test build that turns these features back on for a subset of Insider testers.
Update (July 18): Yesterday, Microsoft released a cumulative update for 18362.1005 (which bumps the build number to 18362.1006) for a subset of Insiders which turns on the features listed in Microsoft's blog post. This is only happening for a subset of Slow Ring testers, as Microsoft indicated would happen.
In addition to these features, today's 19H2 test build includes fixes that were part of the Cumulative update for the May 2019 Update which Microsoft released on Patch Tuesday last week.
Microsoft officials said earlier this month that 19H2 would act as a cumulative update for anyone who is running Windows 10 19H1 (Windows 10 1903). The plan is for this to be a minor update with new features turned off by default. Those not running 1903 who want/need to go to 19H2 once it's available will be able to use the usual tools and processes to move to 19H2.
Given 19H2 will act as a cumulative update for some users, I wondered whether Microsoft was planning to limit the number of times users will have to apply the update in the same way the company limits Cumulative Update deferrals. Here's what Microsoft is going to do, as relayed to me by a spokesperson:
"Customers can control 19H2 like other Feature Updates. For Home and Pro users, control will also remain unchanged and mainly up to the user when to initiate when the update occurs. When Windows 10 devices are at, or will soon reach, end of service, Windows update will continue to automatically initiate a feature update; keeping machines supported and receiving monthly updates is critical to device security and ecosystem health. All customers will now have the ability to pause updates for 35 days.
"Windows Update for Business (WUfB) controls will be unchanged with 1909. 19H2 will be treated in the same fashion as previous Feature Updates, and using WUfB Feature Update deferrals, customers will be able to defer 1909 for up to 365 days while staying on their current feature update while still receiving security and quality updates. A customer who is on 19H1 will continue to receive a security update without 1909 features until 365 days following the publishing 1909.
"While 19H2 will use the same update technology as monthly servicing, IT policies for controlling Feature Updates, such as Deferral, apply."
Windows 10 19H2 (AKA 1909) is expected to begin rolling out to mainstream users around September/October 2019. Microsoft also continues to test the follow-on to Windows 10 19H2 (the 20H1 feature update) in the Fast Ring.