Also updated by Lumia 920 with DP.
If you've been prompted there's update ready and you "dismissed" it before, the first time will fail because it's still downloading the old update. Let it fail. :P
At the second time you'll see the progress bar really move forward in the "Gear" screen. After 30 minutes or so the update is successfully installed.
P.S.: Make sure your phone have enough battery before update if you're not plugging it in power source. My phone started at 82% battery and end with 48% after it's completed. After it's installed, all non-default Apps will turn into "installing" state and you'll have to wait for a while after they're downloaded again.
And then there will be another "Update is ready to download" notification. I decided to wait until all my Apps finished reinstall to continue.
EDIT: I've checked my accounts in Apps got successfully migrated after update, and the Wi-Fi is functioning (not that it had failed before). (Battery power drops to 30%) And then there's 3rd update...
EDIT2: After the 3rd update completes, the migration stuck at step 5, 0% for about 5 minutes, and the remaining completes within a few seconds. The power gone to 20% now and I'll have to find a wall socket.
EDIT3: The Wi-Fi does not work immediately after the update, but after reconnecting it works again. Maybe the DNS got disabled on the way.