Detect browser on ELO device?

We have an alert that pops up when users are accessing our site through Internet Explorer to let them know they are using an incompatible browser. It should only pop up when the user is using Internet Explorer.

We have a client who uses ELO devices to access our website. They are getting this alert. Our website tracks what type of browser the user logged in with. It is returning Firefox version 47, but they are still getting the alert.

This is the function we use to check the browser the customer is using. The function is being used in a control on the master page.

  Public Shared Function IsInternetExplorer() As Boolean
        Dim isIE As Boolean = False
        With HttpContext.Current.Request.Browser
            If UCase(.Browser) = "INTERNETEXPLORER" Or UCase(.Browser) = "IE" Then
                isIE = True
            End If
        End With
        Return isIE
    End Function

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We've tested the website on various browsers, and the alert only pops up on IE, but for some reason our client who uses an ELO device shows the alert. It's not even popping up right away like it's supposed to. It pops up after the user has been logged in for a while and is taking our training. Is there something with ELO devices that alters what browser they are using? We have no way of testing this so we are unsure how to proceed. Is there a way we can correctly detect what browser the ELO is returning?