Microsoft's GDR (general distribution release) updates are the incremental patches that Redmond issues to its Windows Phone OS in-between major step-ups. For example, Windows Phone 8 saw 3 GDR updates, prior to the release of WP 8.1.
Windows Phone 8.1 already has its GDR1 update and word is – a second one is on the way. We previously heard a rumor that it will bring support for 2K resolution, as well as allow the platform to operate with Qualcomm's Snapdragon 805 CPU.
Now, there's a rumor afloat, about some new practical features that GDR2 will bring to WP 8.1 handsets. Reportedly, the Settings menu will finally be sorted alphabetically and will allow users to search through its options, much like one can search through the apps list. Another useful new feature would be the addition of a Mobile data on/off toggle right in the action center. And, of course, the new update will push Cortana to new regions; though, it will still be considered alpha.
Rumors say that the new update should roll out in 2 months. If that's the case – we should expect a Developer Preview to hit select phones earlier and shed more light on the new additions to the OS.