Microsoft has also clarified when versions transition from the consumer-grade release on the "Current Branch" (CB) to the corporate-level CBB, and defined the "grace period" it gives businesses before stopping patches. The gap between CB and CBB was supposed to be about four months, but has been five. Add two months for the 60-day upgrade-now grace, and the gap between the release of and N+2 and the expiration of N should be six to seven months.
Computerworld used that information and an estimate of the timetable for Windows 10's two upgrades of 2017 -- something Microsoft has pledged even though it has not disclosed dates -- to assemble a tentative schedule for enterprises over the next year and a half.
Windows 10 1511, which launched in November 2015 and reached the CBB in April 2016, will reach its end of support (EoS) in September 2017 because the next future version -- 2017's first -- will probably debut on the CB in March. (Six months from then -- four to shift to the CBB, two for the grace period -- would be September.)
Likewise, Windows 10 1607, the version Microsoft shipped in early August 2016 and promoted to the CBB last month, will be retired around April 2018 if, as Computerworld assumed, 2017's second upgrade appears in October of next year. (Six months from October 2017 would be April 2018.)
The three versions set to retire in the next 18 months -- 1507 in March, 1511 in September and 1607 in April 2018 -- will test enterprises' abilities to deal with the new Windows servicing model. Companies better be ready, said Wes Miller, an analyst at Directions on Microsoft.
"They have to learn to adapt to these new cycles of both the more agile Windows and Office," Miller said, adding Office and its three-times-a-year upgrades to the discussion. "The reality is that [versions of Windows] will go out of support, so enterprises must adopt a lifecycle that allows them to deploy the versions that they want, but be ready to upgrade."
Businesses have never had to deal with a Windows upgrade tempo this fast before, nor, said Miller, had to migrate from one major edition of Windows to another while at the same time managing upgrades to the newer as the transition takes place over a year or more.
Miller also added his voice to those of other analysts who have pegged Windows 10 1607 as the candidate enterprises will most likely deploy as they start their moves to the new operating system. "This is the one a lot of businesses will deploy first," Miller said.
Not only will 1607 be supported throughout all next year and the first months of 2018 -- prime time for migrations to begin if companies are to beat the Windows 7 EoS deadline of January 2020 -- but its successor, what Microsoft has dubbed the "Creators Update," appears solidly aimed at consumers, not commercial customers.
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