On stardate 1/9901, the Xerxes re-entered service after undergoing a refit to mk II specifications. She was later refit to mk VI specifications and relaunched on stardate 2/1202, and then later to mk VII specifications around stardate 2/1412. Leonard McCoy was assigned to the Xerxes early on in his Starfleet career. While aboard her, McCoy made several planetfalls for shore leave and developed an idea of what a good liberty port was. (TOS - Star Trek II Short Stories short story: "Under Twin Moons")