Apart from the answer by pinkunicorn Project-GC will match the regions of Geocaching.com when Geocaching.com has regions. Since Geocaching.com uses the regions North Island, South Island and Chatham Islands then Project-GC will use the same regions. If Geocaching.com changes the regions then Project-GC will change them too. Geocaching.com generally changes regions when there has been political updates by the local government. This is not instant and it takes some time for Geocaching.com to update and then further time for Project-GC to follow with the update, that's why you've seen the change recently even though it politically might not be as recent.