It is backwards compatible, in that you can get back to what you had before if you want to.
It is also a beta of a new major version. We are months away from the final stable release. There may be issues and you should expect at least some, because it is a beta version.
If you don't want to be faced with the possibility that you might have to change a few things, or some things may not be ideal or may even be broken at this early stage then please do not install the beta; wait for the final release is ready instead.
This would also have been better as one question per thread, but let's see how we get on keeping it all together. If the thread turns into unreadable spaghetti then I might split things up.
[ul][li]Hotkeys in lister toolbars work identically to in Opus 10, except where noted below.
You shouldn't need to turn toolbar hotkeys on, they should just work, as long as the toolbar itself is turned on in the lister. (And the hotkeys don't clash with other hotkeys, and there's isn't a bug nobody has noticed yet which there could well be as this is a beta).
Have a look in Customize -> Keys.
Note that each window can now have independent toolbars, and the Customize -> Keys list will show you the hotkeys for the most recently active lister. If you turn on toolbars and want them to be the new default, you need to save them (e.g. using Settings -> Set As Default Lister).
And also note that the Keys list is now grouped by type, so the Toolbar hotkeys will be lower down the list in the Customize window than before.
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[li]As far as I can tell and know (Jon may correct me if I'm wrong as he did the new toolbar code), the way floating toolbars are resized has not changed. You may need to set the toolbar into Vertical or Horizontal mode if it's not in the one you want, however. The change notes explain the new system for modifying floating toolbar settings.
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[li]If you give us some examples of things which have changed size we'll see if they can be made the same size as before.
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[li]One extra character in the attributes column does not seem like the end of the world, but I guess it could be made optional if enough people feel the same.
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[li]You can change the file display toolbar background colours via exactly the same place as the file display border colours were configured in Opus 10.
You can also change back to the old file display border, but I recommend at least trying the new way for a while. (It takes a while to adjust to it, and I wasn't sure at first either, but I much prefer it now.)
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[li]The current icons are temporary. I'm not a fan of the blue icons on a blue background either. (I'm using green icons.) We are months away from the final release and icon changes are planned.[/li][/ul]
Maybe there's some confusion here that the Opus 11 public beta is like the betas for minor updates to Opus 10 were. It is not. This is the type of beta we used to give out privately to handful of testers & iterate on for months before a big release. This time we figured we'd do it in public and let anyone who wants to try things and provide feedback. A lot of things have changed, a lot is still to change, and you shouldn't install the betas (at least this early in the process) if you're expecting a finished product. It's very much a beta version.