Just a day after announcing that it had completed development of Windows Phone 7.5, previously code-named Mango, Microsoft delivered updated developer tools and a new build of the OS to programmers. There's just one catch: The Windows Phone 7.5 build that Microsoft handed out isn't the final version; it's a near-final release candidate (RC) build instead.
According to Microsoft's Cliff Simpkins, there's a simple explanation. Though Windows Phone 7.5 is complete, the developer tools aren't. So the pre-release Windows Phone OS build that Microsoft is giving out this week maps to the developer tools version, which Microsoft describes as a "Beta 2 Refresh." Microsoft previously said it would deliver an RC version of the tools to developers in late August.
"What we are providing is a genuine release candidate build [of Windows Phone 7.5], with enough code checked in and APIs locked down that this OS is close enough to RTM that, as a developer, it’s more than capable [enough] to see you through the upcoming RC drop of the tools," Simpkins wrote in a blog post announcing the developer releases. "It's important to remember that until the phone and mobile operator portion of Mango is complete, you're still using a pre-release [OS] on your retail phone, no matter the Microsoft build ... [This code] only includes the Microsoft portion of the [Windows Phone 7.5] update."
Simpkins' comments suggest that the final release of the developer tools, and the "real" final version of Windows Phone 7.5—which will include code from wireless carriers and handset makers—and new phones based on Windows Phone 7.5, won't ship until September at the earliest. But given the historical delta between the finalization of Microsoft's mobile OSs and retail availability, and Simpkins' comments, it's also logical to surmise that the actual time lag might be quite a bit longer than that: October at the earliest.
And this maps very nicely to the schedule my own sources have consistently provided: that Windows Phone 7.5 wouldn't be finalized until September and would then be launched in October, exactly one year after Windows Phone 7, with new devices coming to market beginning that month. We'll see whether that pans out.
There are other questions. For example, when will current Windows Phone users get Windows Phone 7.5 for their first-generation handsets? Microsoft has said all along that Windows Phone 7.5 would be made available for free to all users. But given the issues it had earlier this year supplying much smaller updates, it's also logical to believe that the 7.5 OS, which is a major update, could be delayed even further. (Believe it or not, some current Windows Phone users still haven't gotten a minor update that first shipped way back in February.)
Meanwhile, developers and tech enthusiasts are busy taking apart the RC build of Windows Phone 7.5 to discover what's new. And while I won't be writing much about this until my SuperSite review of Windows Phone 7.5, there are a lot of new features in this build, including Twitter and LinkedIn integration, new branding and logos, a Local Scout app that's pulled outside of the Bing experience, and a ton of fit and finish work. My review of Windows Phone 7.5 will be available on or by the launch event, whenever that happens.