Microsoft has recently added the major platform update to the history page on the Windows Phone website, sitting on top of the three Windows Phone 8 updates



From WPCentral:

This move doesn't mean much apart from Microsoft now publicly lists this upgrade as a "past update" for the platform, leading us to believe the wait is almost over for everyone. As always, consumers will have to wait for the update to pass through both manufacturers and mobile operators.

  Microsoft adds Windows Phone 8.1 to the platform update history page