How to install this aftermarket stereo with a different wire harness?

I had a Sony car stereo installed in my truck. It's an older version and doesn't read my iPhone 4s or iPod touch so I upgraded to the next sony stereo. When I took everything apart I noticed the wire harness plug that goes into the stereo does not fit the newer stereo I bought. Can I replace the plug or do I have to replace the entire harness, or is there a way I can match this harness to other model stereos and just get one that will fit?

You can use to the wiring harness that is already there just as long as you go color to color one wire at a time. Make sure to unplug the harness, so there's no power to it while making your connections.

Look here: ": the 12volt.com". Match the color code for your car.