"If your phone is running Windows 10 Mobile, Microsoft says, it will get all updates, with Microsoft making the final call on when to push the update button."
"That doesn't mean the carriers are completely out of the loop. The Windows Insider program will continue after the launch of Windows 10 Mobile, which means anyone who registers with the Insider program can get early access to updates with new features. The carriers will be part of that testing program, I'm told, probably getting access to builds at the same time as Microsoft's Elite Dogfood group and their input will help Microsoft decide when an update is ready to go out to all devices."
"But those updates will be delivered simultaneously, to all devices on all carriers, meaning much less opportunity for fragmentation."
http://www.windowscentral.com/microsoft-says-it-will-be-charge-windows-10-mobile-update
Great news for windows mobile.
Google has yet to figure it out, less than 10% of android devices boot lollipop. Jellybean, released in 2012, runs on 40% of android devices out there.