IIS10 Max file upload size

Hi, reading a lot of conflicting information regarding this, but trying to upload file sizes larger than 2GB using IIS with PHP. ALL of the PHP side has been configured appropriately, with the following configured in the webconfig:

<requestFiltering>
                <requestLimits maxAllowedContentLength="4294967295" />
            </requestFiltering>

<system.web>
        <httpRuntime maxRequestLength="2147483647" />
    </system.web>

I believe the above are the max setting (apologies not a web administrator) allowed for IIS? However, seem to hit 2Gb hard limit on uploads. Is it correct that IIS has a limit of 2GB, while asp.net 4GB? Is there anything I am overlooking? If indeed 2Gb is the limit, then at least I can draw a line under this and work with that. 

Thanks in advance for any further information and advice.