Just yesterday we were mentioning the latest leaked build of WM6.5, build 28004, which is branched off as WM6.5.3.
This is the latest in a series of builds by Microsoft that continues to make things more finger-friendly, that much is obvious. What is not obvious is where exactly this fits in with Microsoft's plan in regards to WM6.5 and WM7, and whether this ever see the light of day in an official capacity. (Even the much-heralded HTC HD2 is running older builds.)
Looks like the folks at MoPocket have, off the record, spoken to a Microsoft representative at a trade show, and they asked directly about what all of these builds were about.
In short, it is about the coming wave of capacitive devices. According to the rep, capacitive screens are much more responsive but far less accurate than resistive. (But you already knew that.) In turn, things need to be bigger to touch (and this is also why the iPhone does not have handwriting recognition).
As a result ...
"Windows Mobile ... is a UI designed to be able to tap with nearly pixel accuracy. As it stands, the top bar and bottom bar of WM6.5 aren’t tall enough to be able to have clickable buttons without a resistive display."
And what about the HD2, you may ask? After all, it has a capacitive display. Indeed and HTC had to do a lot of in-house work to make that happen, because it's not actually enabled by Microsoft in the OS. That's something we've asked about before on the podcast, and Microsoft is working to make it easier for the OEMs by building it into the OS.
So there you have it. WM6.5.x is real, but looks to be designed for next-generation capacitive displays and might well not be an upgrade for current WM6.5 devices. (Though it could well point to the availability of more capacitive-display phones before the launch of Windows Mobile 7.) It also probably won't be called WM6.5.1 either, just another special variant for specific devices.