[{"id":1,"items":[{id:15,score:10},{id:14,score:100},{id:12,score:1}]},{"id":2,"items":[]}]

db.collection.update({"items.id":{$in:[14,15]}},{$set:{"items.$[element].score":444}},{arrayFilters:[{"element.id":{$in:[14,15]}}],multi:true})