To date, predicting when Microsoft would roll out new feature upgrades to Windows 10 and Office has been a guessing game for IT pros. But starting this September, that situation should become more predictable.

Microsoft is committing to delivering two Windows 10 and two Office client feature upgrades each year, with the target delivery dates being March and September, officials said today, April 20.

Yes, that means "Redstone 3," the next feature update to Windows 10 will begin rolling out in September 2017, Microsoft officials are confirming today. (Before today, we'd only heard from sources that "Redstone 3" would be available "this Fall." And "Redstone 4" should begin rolling out in March 2018, based on this new information.

Prior to today, Microsoft officials had said the company planned to deliver two or three feature updates to Windows 10 at some point during the calendar year. (Last year, however, the company uncharacteristically ended up rolling out only one, the Windows 10 Anniversary Update.) System Center Configuration Manager updates will be aligned with this new twice-annual update model, as well, officials said.

Before today on the Office side, Microsoft was releasing three feature upgrades annually to Office 365 ProPlus -- its client Office suite that is available via many Office 365 subscription plans. Now it will do so twice yearly. (Microsoft has been adding new features and functionality to Office 365 on a monthly, if not more frequent basis.)

Another positive change announced today: Microsoft officials also said today that Microsoft is extending the support period for Windows 10 feature updates and Office 365 ProPlus updates from 12 to 18 months. This will enable IT pros to choose to update once or twice a year, instead of rushing to beat the update-support clock.

Microsoft's plan is to change this cadence, going forward, to improve predictability and "because Office Pro Plus and Windows 10 are often deployed together," said Ron Markezich, corporate vice president of Office 365 Marketing.

On the Office side, this change does not affect "perpetual"/non-subscription Office client apps/suites, Office perpetual clients connecting to on-premises servers or any Office consumer services. It also has no impact on the web versions of the Office apps, like Word Online, Excel Online, and PowerPoint Online. The new policies outlined today are specific to Office 365 ProPlus connecting to Office 365 services.

Office 365 ProPlus, which is available via subscription licensing only, comes with Outlook, Word, Excel, PowerPoint, OneNote, Access, Publisher, Skype for Business, OneDrive for Business, and the Office mobile apps.

Microsoft also is letting its Office customer base know that as of October 13, 2020, Office 365 ProPlus will be the only fully featured, most up-to-date client that will connect to Office 365 services. Anyone using perpetual Office apps and clients may not get all the features at the time they are available to Office 365 ProPlus users. This change reflects what's been happening with many other Microsoft products; the on-premises/local versions are updated less frequently and may not include all of the functionality that is in the cloud versions.

Markezich wasn't ready to say when the next release of Office perpetual will be. If Microsoft follows history, it will likely be two to three years after the company rolled out Office 2016, which happened in 2015. He also was not willing to say yet what the differences will be between Office 365 ProPlus and perpetual Office clients and apps, in terms of features.

Microsoft is adding a number of new Office 365 application compatibility, monitoring, and upgrade assessment tools to try to make Office 365 ProPlus upgrades easier. The company's blog post has more on these tools and more specifics about the new semi-annual upgrade plans.

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