Microsoft reminded customers on Thursday that Windows 7’s first edition, which shipped more than three years ago, will be dropped from support in early April.

At that time, Windows 7 Service Pack 1 (SP1) will become the only officially-supported version of the popular PC operating system.

The retirement of Windows 7 RTM (for “release to manufacturing,” Microsoft’s label for its launch editions) will take place April 9, that month’s date for Patch Tuesday. It will also occur on schedule. Microsoft’s policy is to drop support for an initial edition 24 months after the release of the first service pack.

Microsoft started delivering Windows 7 SP1 to customers as an automatic update in late Feb. 2011, a process that was marred for some customers when the upgrade triggered PC crashes and freezes.

Windows 7 RTM support may be about to end, but that’s not true for Windows 7 overall. Microsoft has committed to support the OS with non-security bug fixes and security patches until Jan. 13, 2015, and with patches only for another five years, or until Jan. 14, 2020.

And Windows 7 RTM will not suddenly go dark on April 10; it will still launch and run. It will not receive any updates—security or otherwise—from that date on, however.