This upgrade totally screws your audio output, it doesn't recognise the conexant device. As usual Dell disclaim any responsibility for this although crowing that windows 10 upgrade will be trouble free. What's the point of an upgrade if it downgrades your computer's functions?
I have reverted to 8.1 (thankfully this works as described). Talking of "works as describes" the windows 10 update page asserts that my computer is compatible with no exceptions- it *** well isn't!