"description":"Optional. The previous ``content`` for this state. This will be present only for state events appearing in the ``timeline``. If this is not a state event, or there is no previous content, this key will be missing."
},
"prev_sender":{
"type":"string",
"description":"Optional. The ``sender`` of the previous event for this state. This will be present only for state events appearing in the ``timeline``. If this is not a state event, or there was no previous event for this state, this key will be missing."
"description":"The MXID of the user who sent this event."
},
"state_key":{
"type":"string",
"description":"Optional. This key will only be present for state events. A unique key which defines the overwriting semantics for this piece of room state."
"description":"Optional. The transaction ID set when this message was sent. This key will only be present for message events sent by the device calling this API."