[{"_id":ObjectId("3a9ccf7de6348936d88b3001"),"name":"Bread_1","version":1},{"_id":ObjectId("3a9ccf7de6348936d88b3002"),"name":"Bread_2","version":2221},{"_id":ObjectId("3a9ccf7de6348936d88b3003"),"name":"Bread_1","version":211},{"_id":ObjectId("3a9ccf7de6348936d88b3004"),"name":"Bread_2","version":222},{"_id":ObjectId("3a9ccf7de6348936d88b3005"),"name":"Bread_3","version":1}]

db.collection.aggregate([{$group:{_id:"$name",version:{$max:"$version"},docs:{$push:"$$ROOT"}}},{$project:{name:"$_id",version:1,_id:{$let:{vars:{id:{$arrayElemAt:[{$filter:{input:"$docs",cond:{$eq:["$$this.version","$version"]}}},0]}},in:"$$id._id"}}}}])