Today, Windows 10 Mobile for selected Lumia has been officially announced by Microsoft. he operating system demoed by Microsoft almost one year ago. Windows Insiders were testing Windows 10 Mobile preview builds and shaping the OS with precious feedback (s). Microsoft promised to announce Windows 10 for older Lumias and other OEMs Windows Devices for the public at end of the last year, between November and December. However, Microsoft keeps delaying the OS and later last year, Microsoft promised that the update will begin rolling to existing Lumias early this year.
As you know the following Lumia will get the update:
•Lumia 635 1GB
•Lumia 636 1GB
•Lumia 638 1GB
•BLU Win HD w510u
•BLU Win HD LTE x150q
•MCJ Madosma Q501
How to download Windows 10 Mobile on supported phones:
To get Windows 10 Mobile on your phone you need to download Update Adviosor app for your Lumia eligible for the upgrade, refer above list. You need to open Update Advisor app on your Lumia and follow the steps listed on the Screen.
Download the app to upgrade: http://aka.ms/W10MUpgradeAdvisor