As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DFW - INFLIGHT DFW-JAX - CREW REPORTED SMOKE VISIBLE IN THE BACK OF THE CABIN AFTER TAKEOFF. EMERGENCY DECLARED, LANDED DFW WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. REPLACED APU DUE TO OIL LEAK. SYSTEM GROUND CHECK NORMAL OPERATION.