I recently ran into an issue where MDT could not determine if our new Dell XPS 13 9365 was a laptop or desktop. After running wmic path win32_systemenclosure get chassistypes, I was able to determine that the chassis type 31 was not listed in MDT’s ZTIGather.wsf. Adding 31 to ZTIGather.wsf (Line 417) as shown below, fixed the issue and MDT was now able to determine that the XPS 13 9365 was a laptop!

Example:

Select Case objInstance.ChassisTypes(0)
Case "8", "9", "10", "11", "12", "14", "18", "21", "31"
	bIsLaptop = true
Case "3", "4", "5", "6", "7", "15", "16"
	bIsDesktop = true
Case "23"
	bIsServer = true
Case Else
	' Do nothing
End Select

Feel free to leave any questions in the comment section!