Update multiple array values

I got this record structure

    {
        "_id" : "CAaveDCnPiC3KE6XS",
        "user_id" : "3zjDhNBRMQPQSeTFa",
        "notifs" : [ 
            {
                "to" : "3zjDhNBRMQPQSeTFa",
                "from" : "cvatYfpebH4X45EvN",
               "seen": false,
                "postedAt" : 1431952371949.0000000000000000
            }, 
            {
                "to" : "3zjDhNBRMQPQSeTFa",
                "from" : "cvatYfpebH4X45EvN",
               "seen": false,
                "postedAt" : 1431952378382.0000000000000000
            },
           {
                "to" : "3zjDhNBRMQPQSeTFa",
                "from" : "cvatYfpebH4X45EvN",
               "seen": true,
                "postedAt" : 1431952378382.0000000000000000
            }
}

I want to update all the seen profperty inside notifs property to true,
I can’t find How to do this, I tried few things nothing worked

Notifications.update({user_id: "sss"}, {$set: {"notifs.seen": true} });

Notifications.update({user_id:this.userId,'notifs.seen': {$ne: true}  },{$set: {'notifs.$.seen': true}});

I have meteorhacks:aggregate package installed, any aggregate solutions are also welcome

Note: $elemmatch is not a solution because it updates only one object in array

Your solution using the .$. modifier seems to be the right way to do this. Unfortunately, it’s not supported in minimongo, which I’m pretty sure means you will need to use a raw collection (so available on the server only).

This post might help

Or you can get the objects with Collection.find, modify the objects with usual JS techniques, then put them back in the DB with Collection.extend from my package https://atmospherejs.com/vjau/mongo-extend if performance is not an issue.