[{identifier:"x",versions:[{name:"test_name",version:"x.x.x"},{name:"test_name",version:"x.x.x"},]},{identifier:"y",versions:[{name:"test_name2",version:"x.x.x"},{name:"test_name2",version:"x.x.x"},]}]

db.collection.update({"versions.name":{$exists:true}},[{$set:{versions:{$map:{input:"$versions",in:{title:"$$this.name",version:"$$this.version"}}}}}])