| 183 | Session Progress | manyfolks, bis |
| 202 | Accepted | events |
| 421 | Extension Required | serverfeatures |
| 422 | Session Timer Too Small | session-timer |
| 489 | Unknown Event | event |
| 490 | Request Updated | early media |
| 580 | Precondition Failure | manyfolks |
Last updated by Henning Schulzrinne