How to Upsert Multiple Object Records Using External Id In Salesforce REST API?

{{endpoint}}/services/data/v61.0/composite/sobjects

This is my endpoint url

And this is how i'am sending the request

{

    "allOrNone" : false,

    "records" : [{

        "attributes" : {"type" : "Account"},

        "Name" : "Test 1",

        "AccountCode" : "1234"

    }, {

        "attributes" : {"type" : "Contact"},

        "Name" : "Test 2",

        "ContactCode" : "5678"

    }]

}

]

 AccountCode & ContactCode is my external id field 

If i try to do patch with single object then it works , 

But I want to do it for multiple object in single request.

Thanks in advance <