Microsoft fans are expecting an update for the Windows Phone 7, “NoDo,” to come this week.

Steve Ballmer said at the Mobile World Congress that the first update for the platform would launch on Tuesday. “NoDo” or ”No Donuts” is a minor upgrade, meant to add copy and past functionality, among other features.

Microsoft has seen some recent problems with its incremental updgrades. In its February update of the Windows Phone, 10 percent of users reported problems. Several Samsung phones were rendered unusable.

There are also questions about the next major update, “Mango,” which had been expected by the end of 2011. Mango, the first big update from the original Windows Phone 7 software, will enable multitasking.

Two writers known for their accurate stories on Microsoft in the past have conflicting reports on the timeline for the launch.

Paul Thurrott, who wrote a book on the Windows Phone, said Friday that his sources inside the company have told him that the Mango update will be delayed until 2012. The update was supposed to be on track for the end of 2011, but Thurrott’s sources said that was a near impossibility.

But ZDNet’s Mary-Jo Foley, also a respected reporter on Windows, has said that her sources have told her that Microsoft’s manufacturers and carriers expect parts of the Mango update no later than this fall, just in time for this year’s holiday season. “So unless Microsoft has gone back very recently and told those partners ‘Just kidding!’ — I still am betting we’ll see WP7s running Mango in 2011,” Foley wrote.