Microsoft might be keeping quiet on the official naming of Windows Phone Mango but it hasn’t stopped the company from dropping hints.
The software giant’s latest Mango developer tools identify Internet Explorer 9 as running on Windows Phone 7.5. Microsoft’s user agent string, used to allow the phone to identify itself to websites, contains the following:

Windows Phone 7.5?
Twitter user Den Delimarsky spotted the reference whilst playing around with the latest developer tools. Microsoft refused to name its next release of Windows Phone at a VIP event in London on Tuesday. Company officials refer to the next release as Windows Phone codename Mango. It’s widely believed that Microsoft will choose to name Mango as 7.5 due to the broad number of features included in the update. WinRumors understands the company has chosen the final naming but is not yet ready to disclose this publicly.
Thanks to WinRumors reader Michael Gillet for the news tip