The only thing I've been able to notice that changed from 3.09 to 3.10 is the iPhone access issue for regular http:// access has been resolved.
I noticed some flakey AD permission issues, but I think they were just a fluke as I've not had then since restarting the LS Pro Duo some time ago.
Hope this helps.
(and no, i don't work for buffalo so i can't post any change logs, I don't have any to post, but i did validate the iphone web access from an iPhone 3G with version 3 (not a 3gS, just a 3G, but assume it's the same deal).