Additional difference in CONN packet between 3.1.1 and 5.0

[JavaSaBr]

For MQTT 3.1.1
If the Password Flag is set to 0, a password MUST NOT be present in the payload [MQTT-3.1.2-20].
If the Password Flag is set to 1, a password MUST be present in the payload [MQTT-3.1.2-21].
If the User Name Flag is set to 0, the Password Flag MUST be set to 0
For MQTT 5.0
The password flag is independent of the username flag.