If you install Opus 11 over Opus 10, without uninstalling in between, then your old configuration is automatically carried over. (The new toolbars will be switched on, but you can switch to your old ones in a couple of clicks: Your old toolbars are still there after you upgrade )
Opus 10 OCB files can also be loaded into Opus 11 in the usual way, if you wish.
If you ever want yo reset to the full default config (not just some aspects of it), uninstalling and reinstalling is the easiest method.