Google announced an updated version of the Gmail email client for iOS devices today. The big new enhancements seem to be "undo," "swipe to archive or delete" and a faster search function. There does not appear to be any support at all for list-unsubscribe functionality, which Gmail's Android client appears to have. Poking around in the new version of the iOS app, I can't get it to trigger any sort of action based on the list-unsubscribe header whatsoever. Strange, given Gmail was long a driver of this functionality.