Flexbox not working in windows 8 phone

Question

I cant seem to get flexbox to work in windows phone.
Am I doing something wrong?
Thanks

#main-box {
    display: flex;
    height: 100%;
    -ms-flex-flow: column;
    flex-flow: column;
}

    #main-box #header {
        height: 50px;
    }

    #main-box #main {
        -ms-flex: 1;
        flex: 1;
        border: solid;
        overflow-y: auto;
    }



    #main-box #footer {
        height: 70px;
    }

 <div id="main-box">
        <div id="header">
  
        </div>
        <div id="main">

        </div>
        <div id="footer">
          
        </div>
    </div>

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Alan Mosley - ThatsIT Solutions