Unrecognized pipeline stage name: '$lookup'

Question

I'm trying to run a script in Robo 3T 1.2.1 which used to work long time ago:

var cursor = db.getCollection('logs').aggregate([
    { $group: { _id: "$userId", count: { $sum: 1 } } },
    { $lookup: { from:"users", localField:"_id", foreignField:"_id", as:"user" } }, 
    { $sort: { count: -1 } }
]);
 
for (var i = 1; i <= 250; i++) {
    current = cursor.next()
    print(current["_id"].toString())
    print(current["user"][0]["currentName"])
    print(current["count"])
}

But it returned an error:

Error:
Assert: command failed: {
    "errmsg" : "exception: Unrecognized pipeline stage name: '$lookup'",
    "code" : 16436,
    "ok" : 0
} : aggregate failed
_getErrorWithCode@src/mongo/shell/utils.js:25:13
doassert@src/mongo/shell/assert.js:16:14
assert.commandWorked@src/mongo/shell/assert.js:370:5
DBCollection.prototype.aggregate@src/mongo/shell/collection.js:1319:5
DBCollection.prototype.aggregate@:1:355
@(shell):1:14

$ mongo --version returned MongoDB shell version: 2.6.12 on the server. Does anyone know what's wrong?

Edit 1: This script used to return the users who have lots of logs, does anyone know if there is an easy way to rewrite it without $lookup?

Answer 1

This is too ancient database. It looks like $lookup was introduced in 3.2 server. See here