{
"type": "group_history_changed",
"latest": "1358877455.000010",
"ts": "1361482916.000003",
"event_ts": "1361482916.000004"
}
A group_history_changed event is sent to all clients in a private channel when bulk changes have occurred to that group's history. When clients receive this message they should reload chat history for the private channel if they have any cached messages before latest.