We are getting nearer to the first update of Windows Phone 8.1 as new update on the Microsoft's OEM website shows documentations for Windows Phone 8.1 GDR1 update. However, if you try to click the links you are asked to log in, making this restricted to just OEM partners.
While Windows Phone 8.1 is still in the early rollout stage, this seems an interesting step from Microsoft. Windows Phone 8.1 Update so far is a bit of a mystery in terms of features for consumers, although native Folder support on the Start screen is confirmed as one of those additions. GDRs though are typically light on features and focus more on underlying fixes and improvements. We reported previously that Microsoft is planning on two OS updates this year for Windows Phone 8.1.
Finally, Microsoft is expected to release GDR1 through their Preview for Developers program as they have in the past e.g. Windows Phone 8.0 Update 3.
Source: Microsoft OEM website; Via: WPCentral