Starting today you need Windows Phone 7.5 to use Marketplace

Today’s the day. This afternoon we started requiring Windows Phone 7.5 on phones to download, buy, update, or review apps in Marketplace. As I’ve written previously, this change applies to both the phone and web Marketplace storefronts. (If you’re just tuning in, please read my earlier post for the full details on why we’re implementing this new requirement.)

Most phones are already running Windows Phone 7.5, which was released last fall, and so most of you won’t notice anything different about how the Marketplace works. However, if your phone has an earlier version of our software installed, you’ll soon start seeing an error message when you try to download a new app, or update one you already own. (I say “soon” because it will take a day or two for the changes we made today to take effect.)

If you do get the error, all you need to do is install the free Windows Phone 7.5 update. You’ll find all the information you need to do that, including an update checklist and easy step-by-step instructions, on Update Central. (Not sure if you have Windows Phone 7.5 installed? Here’s how to check.)

By the way, even if you don’t use Marketplace, there are still lots of great reasons to update. We made hundreds of improvements, big and small, in Windows Phone 7.5. Here’s just a sampling of what I mean. So I’d encourage you to set aside time to update your phone for that reason alone.