As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SMOKE & HISSING SOUND IN THE CABIN NEAR ROWS 26 TO 28. EMER DECLARED FLIGHT DIVERTED & LANDED WITHOUT INCIDENT. ACFT REMOVED FROM SERVICE. UNEVENTFUL LANDING DID NOT LAND OVERWEIGHT. REPLACED LEAKING PERI SEALS AT LT SIDE FWD BULKHEAD ANTI-ICE DUCT. SYS GND CHECKED NORMAL OPERATION CLOSED.