Microsoft today expanded the availability of the new RTM build of Windows 10 version 1803 to the Slow ring.
UPDATE: It has been added to the Release Preview ring as well! –Paul
“We have released Windows 10 Insider Preview Build 17134 (RS4) to Windows Insiders in the Slow ring,” Dona Sarkar wrote in a short update to the original April 16 post in which Microsoft had first announced build 17134 heading to the Fast ring.
This change suggests that rumors of yet another delay for Windows 10 version 1803 are unfounded: Given what happened last time around—when the previous RTM build, build 17133, made its way through all of the public Insider rings despite serious known issues—it’s obvious that Microsoft will be more careful this time around. And sure enough, the delta between the Fast and Slow ring releases this time was four days, double the time that Microsoft previously advanced build 17133.
Anyway, we can only speculate as to the schedule, but we should see a late April public release at the very earliest.