R6400 - firmware version 1.0.1.6 vs 1.0.1.18

Which of these two is the latter firmware?  1.0.1.6 is listed at the top of the download results page, but the release notes aren't dated.  I assume 1.0.1.18 is newer, but given netgear's recent track record, I wouldn't be surprised if "1.0.1.6" is meant to be "1.0.1.60"

[edit] to confuse matters further, one of the "recommended" threads has 1.0.1.6 in the subject line, but dates back to 2012 - i.e. it's unrelated to this specific router.