As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SMOKE AFT LAV WARNING IN FLIGHT. NO VISUAL INDICATIONS OF SMOKE OR FIRE. FIRE TRUCKS CONFIRMED THE SAME FROM THE EXTERIOR. REMOVED AND REPLACED AFT LAV SMOKE DETECTOR IAW AMM 26-16-01 OPS CHECK IS GOOD. NO FURTHER DEFECTS NOTED AT THIS TIME.