After you've installed OnRez for the first time, updating is easy! Every time you start OnRez, it checks for a newer version of itself. If a newer version exists, you'll be asked right away if you want to download it. In some cases, OnRez may tell you that you can't log in until you download the update; this usually happens when a critical security update is released. Otherwise, you'll have a choice of downloading or proceeding with your current OnRez version.
If you decide to download, the main OnRez application will close, and the new version will start to download. You'll see a window showing you the progress of the download. When the new version is finished downloading, it will install itself automatically and then start up. That's all there is to it! You now are running the very latest version of OnRez. And don't worry, all of your settings and preferences will be preserved.
(Note to Windows Vista users: Just as when you installed OnRez for the first time, you may be asked whether you want to allow the OnRez installer to access your system. This is necessary because it needs to copy updated files to your Program Files directory.)