After 18 months since the last major Windows Phone update, Microsoft is finally releasing Windows Phone 8.1 to developers on Monday. The software maker detailed the update at its Build conference less than two weeks ago, and it’s clear the version point increment doesn’t tell the whole story. This is a significant update to Windows Phone 8, with new features like the Cortana digital assistant, a new notification center, and skinned Tiles for the Start Screen. Registered Windows Phone developers can now start downloading the update on their devices, but if you’re not a developer there’s still an easy way to get Windows Phone 8.1 before your carrier is ready to start distributing it. Just head over to the Windows Phone App Studio site and sign in with your Microsoft Account and create a project.