As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
"CARGO DET AFT 28" STATUS MESSAGE APPEARED 40 MINUTES INTO FLIGHT FOLLOWED BY "FIRE CARGO AFT" & 20 MINUTES LATER. QRH EMERGENCY CHECKLIST FOLLOWED AND FLIGHT DIVERTED TO IAD. ON ARRIVAL, THE LOWER AFT CARGO BAY WAS INSPECTED AND FOUND THAT THERE WAS NO EVIDENCE OF FIRE. THE LOWER CARGO SMOKE DETECTOR CONTROLLER WAS REPLACED IAW AMM 26-16-06-400-801 AND EO 4826A003. AN OVERWEIGHT LANDING INSPECTION ACCOMPLISHED AMM 05-51-39 WITH NO FINDINGS.