Microsoft has announced when the next version of Windows with the code name Windows 7 will be shipped sometimes in the first quarter of 2010, according to a letter company senior vice president Bill Veghte sent to Microsoft customers Tuesday.

Microsoft has told that they will public this letter on Microsoft´s. The letter was send to enterprise and business customers.

The title of the letter says "An Update on the Windows Roadmap", which was sent to "Windows Customers". Veghte said "our plan is to deliver Windows 7 approximately three years after the January 2007 general availability launch date of Windows Vista.

Vista ha still compatibility and performance problems and gets tons of critics every day and Windows Vista has not lived up to promises

Veghte went further in addressing customer concerns over Windows 7 application compatibility which has been a big problem with Vista after Microsoft published the final version. But it will be different with Windows 7, he said.

Microsoft will keep using the main core of Windows Vista for Windows 7 but the promise the customers won´t have any compatibility and performance problems with Windows 7.

He said: "You've also let us know you don't want to face the kinds of incompatibility challenges with the next version of Windows you might have experienced early with Windows Vista. As a result, our approach with Windows 7 is to build off the same core architecture as Windows Vista so the investments you and our partners have made in Windows Vista will continue to pay off with Windows 7. Our goal is to ensure the migration process from Windows Vista to Windows 7 is straightforward."