Currently an empty sync response (i.e. without any change) is like that (with formatting added):
{
"account_data": {
"events": []
},
"to_device": {
"events": []
},
"device_lists": {
"changed": [],
"left": []
},
"presence": {
"events": []
},
"rooms": {
"join": {},
"invite": {},
"leave": {}
},
"groups": {
"join": {},
"invite": {},
"leave": {}
},
"device_one_time_keys_count": {
"signed_curve25519": 50
},
"next_batch": "s1195808412_757269739_794431_REDACTED_1021253_37912961_19608850_66812"
}
According to the spec, only next_batch is required, so it could be acceptable to reduce it to:
{
"next_batch": "s1195808412_757269739_794431_REDACTED_1021253_37912961_19608850_66812"
}
I do not know if it will solve the global climat changing problem, but if it's easy to fix, let's save some bytes!