For those who want to start playing with the next version of Windows Phone; Windows Phone 10, a preview is now available.
To get your phone updated with this preview, you need to have the Phone Preview app – which by the way has been updated to be called Windows Insider.
By the way, for those who were already running advance release of the current Windows Phone version using the Preview for developer application this will NOT help you to get this preview.
To get the Windows Insider app, just go to the Store and look for WIndows Insider from your phone or use this link http://www.windowsphone.com/en-us/store/app/windows-insider/ed2b1421-6414-4544-bd8d-06d58ee402a5
Then, once you have the application, just start it and Get preview builds
BUT wait, this is NOT available to all Windows Phone 8.x devices. For this first release, only Nokia Lumia 630, 635, 636, 637, 730 and 830 devices can get this first release. Other devices may get it when future releases will be delivered.
The official statement of Microsoft about this discrimination is
“For this technical preview, we need to start with a small subset of devices in order to isolate OS issues from hardware or board support package issues so we can stabilize the platform. Some context on why we chose these and not higher end phones like the 930/Icon or 1520: We have a feature that will be coming soon called “partition stitching” which will allow us to adjust the OS partition dynamically to create room for the install process to be able to update the OS in-place. Until this comes in, we needed devices which were configured by mobile operators with sufficiently sized OS partitions to allow the in-place upgrade, and many of the bigger phones have very tight OS partitions.”
So if you don’t have a device listed earlier, you still have to wait 