Microsoft is providing Windows 10 Enterprise and Education users still on Version 1511 with more time to move to a newer version of the operating system.

Microsoft officials said on November 14 that “some early enterprise adopters that are still finishing their transition to Windows a service” will get security fixes until April 2018. The official cut-off date for support for Windows 10 1511 was October 10, 2017.

This extra six months of support won’t be offered to users of other versions of Windows 10 1511 (which Microsoft started rolling out to mainstream users in November 2015), officials said. That means Windows 10 Home, Pro, Mobile and Mobile Enterprise must be on Windows 10 Version 1607 or higher to continue to get security and other updates.

Microsoft will make both “critical” and “important” security updates available to Enterprise and Education users running 1511 via all normal channels, including Windows Update, WSUS, Configuration Manager, and the Windows Update catalog.

The “supplemental servicing” for Windows 10 1511 Enterprise and Education users won’t require any additional fees, a spokesperson said.

Microsoft officials denied that this support extension is due to any particular problems users may be experiencing in moving from 1511 to a more recent release of Windows 10.

“Customers with large, complex IT environments are still transitioning into the Windows as a Service model,” said a company spokesperson when I asked for reasons for Microsoft’s latest support extension. “Our early adopter customers are actively moving forward and asked for a few more months to finish their updates.”

“The supplemental servicing security updates are in response to enterprise and education customers with broad early adoption of Windows 10, who are actively moving to Windows as a Service, and are focused specifically to keep them compliant on 1511 while they finish their updates,” the spokesperson added.

Microsoft is currently supporting each new Windows 10 feature update for 18 months from the time it begins rolling out to mainstream users.

The successor to 1511, known as Windows 10 1607 — which began rolling out in August 2017 — is currently slated to be supported until some time in March 2018. Version 1703, which began rolling out in April 2017, is slated to exit support in September 2018, and the just-released Windows 10 version 1709, which began rolling out in October 2017, should be supported until March 2019.