[nhc-bugs] What's the correct procedure for upgrading?

I hope nhc-bugs is the correct venue for this question. I installed NHC 1.16 on Cygwin (Windows XP), had some problems with it, and then realized I had grabbed an old package. I'm going to upgrade to 1.18 and try again. However, I'm a little bit concerned about the right way to do it. I haven't found any instructions for upgrading properly. Do I just install 1.18 and forget about 1.16? Or should I delete all of the 1.16 files first? I didn't see a Makefile target "uninstall", although there are some "*clean*" options there. Perhaps you could add this topic to your website? Thanks. Charles Hethcoat