Assuming you don't want to reset your whole configuration, let's look at things you might want to update after installing Directory Opus 13 over 12.
None of this is mandatory. In each case, it's up to you whether you keep what you had, update to the new defaults, or combine elements of both.
HOW TO: Enable/fix playback of various media formats in Opus (re-written for Opus 13)
There are lots of new things in Preferences, but the lists below are more about old functionality which is now configured in a different way, or things you may want to change if you're used to older versions.
Remember to use Settings > Backup & Restore regularly to save a copy of your configuration!