The v2 devices are kobo7. My update check bot just found out.
Here are the API URLs for proof:
http://api.kobobooks.com/1.0/Upgrade...79/kobo/0.0/N0
http://api.kobobooks.com/1.0/Upgrade...78/kobo/0.0/N0
There is one unfortunate (but possibly temporary) change though: The full version number does not seem to be in the upgrade url anymore (this will make the checks for my firmware page harder). If anyone has any ideas about extracting the version (preferably without downloading the whole zip), I'd really appreciate hearing it. The only way I've found is the second string after "Mozilla/5.0 (Linux; U; Android 2.0; en-us;) AppleWebKit/%1 (KHTML, like Gecko) Version/4.0 Mobile Safari/%1 (Kobo Touch %2/%3)" in libnickel.