What bloggers and developers have picked up on is “RC1” though many have overlooked the term “Escrow.” In a statement, all Microsoft will say is “The recently refreshed Windows Phone Developer Tools CTP includes release candidate 1 code. We have no further information to share regarding when Windows Phone 7 will reach RTM [Release To Manufacturing].”

The term “escrow” has been used at Microsoft for years, writes Paul Thurrott, the news editor at Windows IT Pro, and creator of the Windows Phone Secrets . It “means that if it [the code] passes certain quality criteria it will be declared the actual release candidate 1 build. If not, fixes will be made and the build will be incremented, and they’ll try again,” he writes. But he considers the April build to be a “near-final look” at the new smartphone platform.

Thurrott has posted at his SuperSite for Windows blog nearly 70 Windows Phone from the refreshed emulator, often with several from each application. The images give a broad overview of the UI’s look and feel, though they don’t give a sense of the various “hubs” that Microsoft uses to collect and order content, or the navigation between these.

One set of three images shows the voicemail screen, the phone dialer (a minimalist set of dark gray rectangles), and settings for the voice features. Another set show screens from contacts, dubbed “people” in Windows Phone, including adding a contact, and adding online accounts such as Windows Live or Facebook.

He also has more images from the Office “hub” of Windows Phone 7 – the location of the mobile Microsoft Office applications and especially the all-important OneNote note-taking software. He shows OneNote’s main , and an initial list of OneNote resources and