The article says it was the last one in service/last to be decommissioned in the USN which I think is accurate.
Unless you're counting LHDs
I second that and to avoid any doubt from the horse's mouth as it were, (guess no one can claim that the USN isn't authoritative
Kitty Hawk had been the Navy's oldest active warship since 1998 and turns over the title to the nuclear-powered aircraft carrier USS Enterprise (CVN 65). Kitty Hawk was also the Navy's last remaining diesel-fueled aircraft carrier.