nc-tester commented on 406 Error When Posting Order

As things stand, it cannot be configured to use JSON instead of XML (it's beyond my control). I submitted the following XML, and still received a 400 error. Is there still something syntactically incorrect? Obviously because of the shift toward JSON, there isn't much documentation on suitable syntax.

<order>
    <line-items>
        <line-item>
            <quantity>1</quantity>
            <variant-id>739391395</variant-id>
        </line-item>
        <line-item>
            <quantity>1</quantity>
            <variant-id>739382303</variant-id>
        </line-item>
    </line-items>
</order>