Eagle eyed users have been able to locate a hidden Phone Insider app in Windows phone store that uses Windows Insider registration for pushing new Windows Mobile 10 OS upgrade to Windows phone. It seems enthusiasts won’t need to go for a developer registration and if you have registered to Windows Insider program for Windows 10, you don’t even need to register. When I checked with my insider account, it said no update for your windows RT device and if you try to check for other packages, you need to have a official Microsoft account.
Phone Insider Details:
The Phone Insider application provides registered Windows Insiders the ability to receive pre-release OS updates on their phone, directly from Microsoft. For more information about registering and becoming a Windows Insider visit http://insider.windows.com.
Thanks Amit for the tip. Cheers!!