i am getting local time zone as null in my activity object

[Anubhooti_Bhatnagar]

Activity Object: {
"type": "message",
"id": "1566815985480",
"timestamp": "2019-08-26T10:39:45.5003126+00:00",
"localTimestamp": "2019-08-26T16:09:45.5003126+05:30",
"localTimezone": null,