Microsoft will issue the final security update for the debut version of Windows 10 tomorrow.
Windows 10 1507 -- Microsoft tags feature upgrades with a yymm label -- will receive its last security patches on May 9. The retirement date had been quietly announced last month when it appeared on several support documents.
"The time has now come to end servicing for version 1507," one of those documents stated.
Tomorrow is also May's "Patch Tuesday," the month's release of security updates for Microsoft's products. The company's selection of May 9, as well as answers several officials gave last week during an online Q&A, signal that it will retire Windows 10's versions on Patch Tuesdays, just as it has ended support for other OS editions on those 12 days throughout the year.
Stopping support for Windows 10 editions is as important to Microsoft's "Windows-as-a-service" model as is its cadence of shipping two feature upgrades annually. The company has pledged to support an individual edition, such as 1507, for just 18 months, not the 10 years it provided for previous Windows editions.
The cut-off guaranteed Microsoft would not be burdened by a requirement to maintain an increasing number of versions, letting it instead focus on just two iterations of Windows 10 at a time.
In the end, Microsoft supported Windows 10 1507 for 21 months rather than the pledged 18.
Using the 18-month lifecycle, Windows 10's second edition, version 1511 -- released Nov. 12, 2015 -- should also fall from support this month. But because of other arcane rules Microsoft follows, 1511 will be supported at least through October, according to Nathan Mercer, a senior product marketing manager, in a reply during last week's Q&A.
That would provide 1511 with two years of support.
Microsoft hasn't set end-of-support dates for Windows 10 1607 or 1703, the upgrades released in August 2016 and April 2017. Under the 18-month guideline, 1607 should head to retirement in January 2018 and 1703 shuffle off in September 2018. However, it's likely that Microsoft will extend 1607's date of demise, as it did to 1507 and 1511, to separate it from the latter.
Windows 10 1507 LTSB -- the "Long-term Servicing Branch" version of the original release -- will continue to receive security updates, Microsoft has said. The LTSB track is available only to customers running Windows 10 Enterprise.
Although Windows 10 1507 will continue to operate without restrictions after tomorrow, without future bug fixes, the operating system "could become more vulnerable to security risks and viruses," Microsoft warned. To continue to receive updates, users must upgrade to 1511 or later.