Owners of Windows Phone handsets who have yet to upgrade to version 7.5 of the firmware will soon find themselves locked out of the platform's app store.

According to a post on the official Windows Phone blog, those running older versions of the OS will soon receive an error message when trying to download Marketplace content – whether new apps, or updates to those already on their device.

Moving with the market

"Starting in the next few weeks anybody who wants to buy or download a new app, update an existing app, or submit app reviews to Marketplace will need Windows Phone 7.5 on their phone," detailed director of program management Mazhar Mohammed.

"Requiring Windows Phone 7.5 is part of a larger effort aimed at improving Marketplace performance and security, and paving the way for even faster growth and more new features."

Microsoft has also removed the option to shop for Windows Phone apps from its Zune PC software, responding to stats that show Windows Phone users favour the on-device store or the recently launched web-based Marketplace

Said developments follow rumours yet to be denied by Microsoft that existing Windows Phone owners will not be able to upgrade to Windows Phone 8 – better known as Apollo – when it launches later in 2012.

[source: Windows Phone blog]