[{"bookmaker":"Bet365","sport":"Football","data":[{"lastUpdate":"2372273273","events":[1,2]},{"lastUpdate":"2372234421","events":[3,4]},{"lastUpdate":"2375343461","events":[5,6]}]}]

db.collection.update({"data.lastUpdate":{"$lt":"2372273273"}},[{"$set":{"data":{"$map":{"input":"$data","in":{"$cond":[{"$lt":["$$this.lastUpdate","2372273273"]},{"$mergeObjects":["$$this",{"events":[]}]},"$$this"]}}}}}])