As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAH TO ATL - AFTER LEVELING OFF IN CRUISE FLIGHT, THE CREW RECEIVED AN APU HIGH TEMP MESSAGE ON EICAS. AFTER FOLLOWING THE APPROPRIATE QRH CHECKLISTS THE FLIGHT DIVERTED TO MGM WHERE IT LANDED WITHOUT INCIDENT. MAINTENANCE INSPECTED THE APU AND FOUND IT WAS LOW ON OIL. AFTER PROPERLY SERVICING THE APU WITH OIL, IT OPERATED NORMALLY AND THE AIRCRAFT WAS RELEASED TO SERVICE.