I got it. The release notes are identical to the 2.0 release, so I have no idea what's new.
All I know is that it didn't fix either bug I reported, namely:
1. Using remote commands in HQ mode doesn't cause the application to rebuffer. As such when the buffer is very large, as it is over 3G, the result of a remote commands take upwards of 30 seconds to display. For example seeing the result of changing a channel can take 10 to 30 seconds.
2. If you open the Guide and change a channel, then later on if you open the guide and close it without selecting a channel, the app will change to the original channel you selected. For example, open Guide and pick channel 200, then change to channel 100. Open guide again and choose close, app will change to channel 200 even though you didn't select that.
I think I found what's new. They added green dots to the options screen in both SD and HQ mode.
In SD mode I see 1 green dot, in HQ mode I see three green dots.
The support articles for the iPhone app haven't been updated, but the green dots are explained in this article for the iPad app (though there are some differences):