Hello Abhijit Jagtap,
Thanks for reaching out!
The 'receivedDateTime' tells the date and time the message was 'received' by the service whereas 'sentDateTime' tells the date and time the message was 'sent'. For both the properties, the date and time information use ISO 8601 format and is always in UTC time. For example, midnight UTC on Jan 1, 2022 is 2022-01-01T00:00:00Z
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If you are referring to the first message in a new conversation, the value of 'receivedDateTime' will be the date and time nearly equal to when the message was sent by the user i.e., with a few seconds difference. Note that if the message was delayed in transit, the 'receivedDateTime' value may not reflect the time when the message was originally sent by the user.
Refer below screenshot:
Hope this helps.
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