We expect the final build to be in the range of 8.15.xxxxx.xx, but higher than what can be seen in the above screenshot. As per the info we got, Windows Phone 9 may come with a Build Id of 8.20.XXXXX.XX, though that may change.
The developers preview enabled device should able to get the taste of new features and changes brought by GDR2 in October. Confirming a date is not possible as that keeps on changing.
What GDR2 brings:
We received a tip claiming Settings sorting, Mobile data toggle & Cortana for more markets. This still needs to be confirmed with our sources, so take it with a pinch of salt. However, we can confirm Cortana coming to more European markets and the Alpha Cortana in India, Australia and Canada coming out of Beta.
We have earlier reported that GDR2 may bring support for 2K resolution display and Snapdragon 805 processor. However, now it seems the broader hardware support may or mayn’t arrive with GDR2. Microsoft may have it now planned for Windows Phone 9, which comes to developers preview devices in early 2015.