No official word from Microsoft yet, but it does look like Windows Phone 7.5 Mango will begin rolling out this week. That's two weeks after it was expected.According to WinRumors, the date had already been previously talked about, but just last week, the Windows Phone Dev Podcast team said in a bulletin: 'Next week is going to be a big week for Windows Phone. We have been told by various sources that Mango will be dropping, and the final tools will be dropping for developers. So that would be interesting and something to look forward to.'Previous Mango-related predictions by the teams have become a reality, so this one should be accurate. However, it's not quite clear what 'dropping' means. Presumably it means the rollout of the upgraded operating system will start to filter down. If you've got a SIM-free phone, there's every chance you'll be offered the upgrade in a matter of days. However, if your WP7 handset is through a network, you'll have to allow time for that network to test and update the OS for their respective phones. That could take weeks.When it does land, you'll see additions like Twitter and LinkedIn support added to the Facebook functionality already there, a new Threads feature showing communication with a particular friend across IMs, email and text, a new, desktop-like Internet Explorer 9 browser, including local search functionality, as well as a wider selection of apps – up to 18,000 to choose from apparently.New phones likely to launch too - stay tuned for details of those in the coming weeks.