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Microsoft on Monday released a preview of Windows Phone 8.1 , which delivers a handful of new features to the company's smartphone operating system. In addition to home screen wallpapers, an extra live tiles column, and a notification center, the update includes Microsoft's Cortana voice assistant. Here's how and when you can get Windows Phone 8.1 on your device.

Become a developer

The fastest way to get the Windows Phone 8.1 update is to become a developer. Those users who have an active Windows Phone Dev Center account, an active App Studio account, or have a registered developer device can get the update directly from Microsoft through the Preview for Developers app in the Windows Phone Store.

Signing up for a Windows Phone Dev Center account requires a payment of $19 per year (or €14 per year in Europe and £12 per year in the U.K.). If you simply can't wait to get the latest updates and aren't willing to shell out some cash, you can register your device as a "developer device" for free. Please be aware, however, that installing the preview update will void your warranty and that you will be unable to revert back to an earlier version of the operating system.

To "developer unlock" your device, you must first download and install the Windows Phone SDK (sorry Mac users, it's Windows only). Connect your Windows Phone to your computer and open the Windows Phone Developer Registration. Verify that your phone has been identified, click the "Register" button, and sign in to your Microsoft account.

Screenshot by Dan Graziano/CNET

Next you will have to download the Preview for Developers app from the Windows Phone Store. Open the app and check the box that reads "Enable Preview for Developers." To download the Windows Phone 8.1 update, go to the phone's settings, scroll down to phone update, and check for updates. If your phone was properly unlocked the Windows Phone 8.1 preview update will be waiting for you.

Buy a new phone

A safer route would be to purchase one of Nokia's three new smartphones: the Lumia 930 , Lumia 630 , or Lumia 635. All three of these devices are slated to be available in May and will come with Windows Phone 8.1 already preloaded on them.

Wait for the update

If you aren't in the market for a new smartphone or you would like to hold on to your existing device, you can also wait for your carrier to push the update to you. While timeframes will vary for each carrier, Microsoft has said that the Windows Phone 8.1 is expected to arrive on Windows Phone 8 devices sometime this summer.