Having launched its new smart phone software, Windows Phone 7 series,  in February, Microsoft ha revealed that the new devices won't be able to run older applications.

This follows an eralier revelation that existing Windows Mobile 6.5 devices won't be able to upgrade to the new platform.
The company is selling the incompatibility to end users as a clean break and making a big effort to position itself as doing something "different" in the market.
According to Microsoft executive Charlie Kindel, writing on the company's blog, "Different is often good. Especially when it’s different for good reasons. Windows Phone 7 Series is different because we reset everything we were doing to focus on end user experience."
He says Microsoft had to change its stragetgy to accommodate what developers were asking for and now focuses on delivering an integrated end user experience by investing in the developer platform and developer experience to drive a standardised hardware platform.
"The Windows Phone 7 Series developer platform is as different as the new user experience," he says. "It’s fresh. It’s pure. And it’s powerful.
"We took the feedback we gathered from developers, looked at the full potential of Windows Phone 7 Series and landed on three  basic goals for the platform we’re delivering."
These goals, says Kindel, are:
* Enable end users to be able to personalize their phone experience through a large library of innovative, compelling, games and applications;
* Enable developers to profit; and
* Advance the “3 screen plus cloud” vision.
"For us, the cost of going from good to great is a clean break from the past," he says. One result of this is previous Windows mobile applications will not run on Windows Phone 7 Series.
"To be clear, we will continue to work with our partners to deliver new devices based on Windows Mobile 6.5 and will support those products for many years to come, so it’s not as though one line ends as soon as the other begins."