1. Optimised request: client has item groups list of specific version already and asks about the changed one:

Edit 
				
					{
  "id": "__ID__",
  "api": "1.0",
  "method": "hub.scenes.item.groups.list",
  "params": {
    "version": 24
  }
}
Edit 
				
					{
"api": "1.0",
"error": null,
"id": "633216245ab7be12415365c4",
"result": {
"version": 24
}
}