Finally found out the issue guys, You need to install the developer preview before installing the OAU (On Air Update), as simple as that. Don't worry I will retrace the path I have travelled for installing the update.
1. if you don't have an active Windows Phone Dev Center account; OR not running a registered developer device (‘dev unlocked’ phone), you need to create an
App Studio account; and after that just create any app from the available templates.
2. Use ur
BingVision to install this app
3. Install , open and enter the details when asked by the app. Login with your microsoft account (make sure to use the same account used for creating the app studio account ). Get the developer preview and restart your phone. You can make sure you got the update by going to
Settings and check whether the previously named
Flight Mode now changed to
Airplane Mode. (Also
Mobile Network --> Cellular ).
4. Once this is available, you can update your phone.
Please let me know whether this worked for you or not. It worked for me :) All the best Folks .