Hello, Robert.
Unfortunately we, being a small company, can't possibly test our web server with every .net framework out there, but it should be fairly easy for you to try. Simply install UWS and register your application using UWS Explorer - it has nice simple wizard for that, and please share your findings so we could be more helpful when someone else asks us about this.
We have not tested UWS with Windows XP Embedded, but read that XPE does not support http.sys API. If yo try installing UWS on XPE, our installer will tell you if http.sys is not present.
Best regards,
UltiDev Team.
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