Windows Phone devices must now be running on the latest 7.5 Mango software in order to download, buy, update or review applications from Microsoft’s Marketplace.

Microsoft warned us in April that it was making some fundamental changes to the way apps could be purchased, including making it no longer possible to get apps via Zune.

These changes have now been implemented, with users needing to upgrade to Windows Phone 7.5 Mango if they wish to continue accessing what apps are available.

Anyone who tries to download an app or update an existing one they purchased from the Marketplace will now receive an error message. Microsoft has said it may take a couple of days for the update to become a prerequisite on all devices but  - if you haven’t already - you’ll want that update sharpish 

To update your Windows Phone to Mango 7.5 simply plug your device into your computer.

Have you upgraded to Windows Phone 7.5 Mango? Notice any improvements?