It looks like those Threshold tipsters were right on the money about Microsoft's next-generation Windows release .

According to a January 11 report from Windows SuperSite's Paul Thurrott, Microsoft Threshold looks to be a spring 2015 release wave. Specifically, if Microsoft sticks to schedule, Threshold should crest around April 2015, Thurrott said he's been told by his own sources.

Microsoft is going to disclose its Threshold plans at a "vision" level at its Build conference in San Francisco in April 2014 , Thurrott said. If this happens, it'll be a back to the future moment -- and one that will be welcomed by many in Microsoft's developer and user communities. Microsoft's Windows division finally will begin sharing at least some details about its future Windows plans publicly again.

Thurrott said the Windows team is expecting to disclose that Threshold development will start in April of this year, and that there will be three milestones, meaning test builds before the product is released to manufacturing and made available in April 2015 release.

Currently, as I mentioned as part of a recent Windows Weekly episode's "Rumor of the Week," Microsoft is moving toward naming Threshold "Windows 9," so as to distance and differentiate itself from Windows 8, Thurrott said he's heard from his contacts.

In addition to further unifying Windows and Windows Phone, the Threshold release also will feature the 2.0 version of Microsoft's "Metro" user interface/design language, Thurrott is reporting.

As I noted back in October last year, "Threshold" is the codename for a wave of releases , the same way that "Blue" was the codename for the latest Windows 8.1, Windows Server 2012 R2 and soon-to-be-released Windows Phone 8.1 releases.

Threshold will include updates to all three Windows OS platforms (Xbox One, Windows and Windows Phone) that will advance them in a way to share even more common elements, my sources have said. It's not clear from Thurrott's report how much Microsoft execs will say at Build about the Windows Phone and Xbox "Threshold" deliverables.