Microsoft has confirmed that Nokia's latest software version 2.0 of the X platform will not embrace the existing Nokia X, X+ and XL handsets due to hardware incompatibility.

The excitement surrounding the launch of the new Nokia X smartphone, the X2, dimmed a little when Microsoft revealed some disappointing news to its existing Nokia X customers. Owners of less-than-a-year-old Nokia X, X+ and XL smartphones will not be entitled to the latest Nokia X platform 2.0 update, which brings a slew of UI changes and other improvements. Launched alongside the Nokia X2, the Nokia X software platform 2.0 is incompatible with the hardware found on the original Nokia X trio, the Finnish phone maker said.

The New Nokia X platform 2.0 is based on Android 4.3 Jelly Bean, but heavily customized to run Nokia and Microsoft apps and services. The software update gets four tiles per line on the home screen, each of which can be rearranged and resized. The new platform, which is used by the Nokia X2 smartphone, offers a richer, faster and simpler user experience with quick access to home screen icons, Fastlane, notification manager and task manager.

With the Nokia X smartphones entering the market just this year, it could upset the owners of Nokia X, X+ and XL handsets for not being able to upgrade to the new platform. The move is quite similar to what Microsoft did with Windows 7.x and Windows Phone 8 transition.

Yannis Paniaras, head of the Mobile Phones UX Design Studio at Microsoft in Beijing, blamed the hardware on the old Nokia X smartphones, which is keeping the customers from upgrading to the new platform, but promises other improvements in the future.

"Because of the necessary hardware upgrades, the Nokia X software platform 2.0 won't be available on Nokia X, Nokia X+ or Nokia XL," Paniaras wrote in theNokia Conversations blog. "However, more updates will be coming to further improve the experience of those devices in the coming months."

Nokia launched its X2 dual-SIM smartphone Tuesday, packed with a 4.3-inch display, upgraded dual-core processor, 1GB RAM, 5-megapixel camera and a front facing camera. The smartphone continues the affordable pricing structure with a $135 price tag.