Microsoft yesterday reminded customers 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 February 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.

Windows 7 SP1 may be the only service pack Microsoft issues for the operating system during its 10-year lifespan. Last October, the tech website The Register, citing unnamed sources, reported that Microsoft would forgo SP2.

That would continue the trend of Microsoft gradually reducing the number of service packs it releases. Windows XP, launched in fall 2001, had three SPs, while 2007's Windows Vista had only two.

Some longtime Windows watchers, including ZDNet's Mary Jo Foley, believe Microsoft will replace service packs with more frequent, smaller-sized upgrades, perhaps annually. Microsoft, however, has declined to officially comment on that speculation.

Analysts were dubious last year that Microsoft could pull off a yearly upgrade schedule, with some contending that enterprises would reject the change unless the company takes the drastic step of splitting Windows, with one version for businesses, another for consumers.

"What Microsoft needs to do is to move to different cycles for consumer versus enterprise, since a faster pace has mostly consumer repercussions," Michael Silver of Gartner said then.

Windows 7 has been a successful replacement for the aging Windows XP, which falls off the support list in April 2014. According to the latest data from Web metrics company Net Applications, Windows 7 powered 48.5% of all Windows PCs in January.

Windows 7 SP1 can be downloaded manually from Microsoft's website, or retrieved by turning on Automatic Updates. To check which operating system is currently installed, users should follow the instructions Microsoft has posted here.

Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, on Google+, or subscribe to Gregg's RSS feed . His email address is gkeizer@computerworld.com.

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