Update the software and system

Sorry, but iFixit isn't the right place to find answers to either part of your questions. For system updates, there should be plenty of information available on the Motorola website and there are usually support forums available to help you.

With regard to trade-in value, that's going to be heavily dependent on the carrier and their trade-in policies; we can't really help with that either. iFixit focuses on hardware repair issues, so software and phone values aren't something you'll find on this site. If you go to your carrier's website, they'll have a section on trade-in value, or you can try one of the many online sites that will buy your phone. Search for something like "what is my phone worth trade in" and you'll get quite a few results to look through.