- Packet size: 1-2 bytes. 2 byte mode looks defective on Worlds 1920, and non-existent on 1904 and below.
- ObjID: Either 1 byte, or if byte is 0, then after that a thing I will call a WorldsString. 254 is a special destination called "CO"
- Packet type: 1 byte
- Packet data
If the initial ObjID is "CO" (254), Packet data consists of ObjIDs followed by packet data for the packet type.
WorldsString: 1 byte for remaining length in bytes, then the string in Modified UTF-8 encoding