204° Fahrenheit

You can technically eat pork at 165° Fahrenheit.  But this isn't doing justice to the pork shoulder/pork butt for all your hard work.  At 165 degrees, you will have a chewy mess.

When you are slow cooking a pork shoulder/pork butt, the internal temperature is rising.  There is a good amount of fat inside pork.  This is where a lot of the flavor of a pork shoulder comes from.

If you keep the pork shoulder/pork butt on until the internal temperature is 195 - °204° Fahrenheit, this will allow the fat to melt and render into the meat and have the pork melt in your mouth.