I just created a sharded cluster (no upgrade, all new) with mongo version: 4.2.3

Then went to make an aggregate as usual and found the following error:

Error: command failed: {
	"ok" : 0,
	"errmsg" : "unrecognized field 'useNewUpsert'",
	"code" : 9,
	"codeName" : "FailedToParse",
	"operationTime" : Timestamp(1582558484, 1),
	"$clusterTime" : {
		"clusterTime" : Timestamp(1582558484, 1),
		"signature" : {
			"hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
			"keyId" : NumberLong(0)
		}
	}
} : aggregate failed 

The  aggregate code is very simple:

db.getCollection('sigma').aggregate([
    {"$limit": 100}
])

Im unable to find any information about this field or how to disable it. Its referenced inside github mongo code and this is the only result in google I can find. Find commands works ok, aggregate is failing in php driver, robomongo and the mongo shell.