Microsoft last week released the first preview of what will become Windows 10 version 1903, the opening feature upgrade of next year, slated to ship in the spring.
The debut of what Microsoft calls the "Skip Ahead" build for Windows 10 1903 also hints that the release of this fall's upgrade, aka 1809, will take place in September. If so, it would be the first time since late-2015 that the actual delivery date matched the numerical label.
On July 25, Microsoft forked the 1809 preview of Windows 10 - as it's done before when a feature upgrade approaches - so developers could continue to deliver betas for that build while also beginning to work on the next-in-line, 1903. (Microsoft uses a yymm labeling system to mark its Windows 10 feature upgrades; 1809 should indicate a September 2018 release, while 1903 would be a March 2019 release.)
When it forks preview code, Microsoft provides the even-further-in-the-future build, in this case, 1903, to Windows Insider participants who earlier volunteered for Skip Ahead. As the current feature upgrade gets close to release, Microsoft switches Skip Ahead users to the following upgrade, so that engineers can start collecting feedback on that version even as they keep polishing the one set to launch soon. The bulk of Insiders remain on the latter.
Think of the Skip Ahead debut as a warning bell, like the one rung at track meets when racers start the final lap: When Microsoft begins to ship Skip Ahead code, it's close to wrapping up the impending feature upgrade.
In 2017, as Windows 10 1709 (aka "Fall Creators Update") neared completion, Microsoft first forked the preview code and distributed a different build to Skip Aheaders on Aug. 31. Windows 10 1709 began its release cycle on Oct. 17, or 47 days later. With this year's version 1803, Skip Ahead debuted Feb. 14, or 75 days before the April 30 release of that upgrade.
(Windows 10 1803's original launch date, reportedly April 10 - which was one of two dates Computerworld had forecast in February - was postponed by 20 days after a deal-breaking bug was uncovered at nearly the last minute.)
For one estimate of the release date for Windows 10 1809, Computerworld added 47 days to July 25, arriving at Sept. 10. A second estimate was generated by adding 61 days - the average of the two previous Skip Ahead triggers - to July 25, resulting in a Sept. 24 rollout.
Because the last three feature upgrades launched on either a Monday or Tuesday - April 11, 2017 for version 1703; Oct. 17, 2017 for 1709; April 30, 2018 for 1803 - Sept. 10 or 11 would be the most likely release dates for 1809, absent a show-stopping problem like the bug before 1803's launch. Computerworld's alternate forecast would be September 24 or 25, also a Monday/Tuesday combination, because it would match the previous upgrades' average time-between-Skip-Ahead-and-release.
If Microsoft does release Windows 10 1809 in September, it would be the first time since November 2015 that the company has matched delivery date and the upgrade's label. Version 1511 debuted Nov. 10, 2015. The four subsequent upgrades, 1607, 1703, 1709 and 1803, all missed their release months by between 2 and 30 days. (Version 1607 came the nearest, releasing Aug. 2, 2016.)
Although Microsoft has never expressly tied itself to March and September release months - in a support document, it gives itself wiggle room by stating that feature upgrades will be released "twice per year, around March and September [emphasis added]" - the disconnect between release and numerical designation has always seemed odd.
Issuing feature upgrades during the appointed months would be a sign that Microsoft has gotten a better handle on the rapid development tempo it has at times struggled with executing. It would also be a step toward a more predictable schedule, which was the point of the pledge it made over a year ago to issue a pair of feature upgrades annually.