[{"_id":ObjectId("6032a5ad80443334a35f2232"),"List":[{"_id":ObjectId("6032a5af80443334a35f2234"),"customData":[{"_id":ObjectId("6032a5bc80443334a35f223c"),"systemUpdate_DT":null,"field_id":ObjectId("6032a5bc80443334a35f223b")},{"_id":ObjectId("6032a5c280443334a35f223e"),"systemUpdate_DT":null,"field_id":ObjectId("6032a5c280443334a35f223d")}]},{"_id":ObjectId("6032a5b080443334a35f2236"),"customData":[{"_id":ObjectId("6032a5bc80443334a35f223c"),"systemUpdate_DT":null,"field_id":ObjectId("6032a5bc80443334a35f223b")},{"_id":ObjectId("6032a5c280443334a35f223e"),"systemUpdate_DT":null,"field_id":ObjectId("6032a5c280443334a35f223a")}]}]}]

db.collection.update({"_id":ObjectId("6032a5ad80443334a35f2232")},{$set:{"List.$[list].customData.$[customData].systemUpdate_DT":"updatedDTTM"}},{"multi":false,"upsert":false,arrayFilters:[{"list._id":{"$eq":ObjectId("6032a5af80443334a35f2234")}},{"customData._id":{"$eq":ObjectId("6032a5bc80443334a35f223c")}}]})