Sending payload. which attributes are optional

“reference”: “abcd1234”, // reference which will be used on ack or error (this can be a random string)
“confirmed”: true, // whether the payload must be sent as confirmed data down or not
“fPort”: 10, // FPort to use (must be > 0)
“data”: “…” // base64 encoded data (plaintext, will be encrypted by LoRa Server)
“object”: { // decoded object (when application coded has been configured)
“temperatureSensor”: {“1”: 25}, // when providing the ‘object’, you can omit ‘data’
“humiditySensor”: {“1”: 32}
I am new for LoRa Server.
from the above payload (on your documentation) which attributes are optional;
and can anyone explain each attribute for me;