Since upgrading, two of my customizations went back to default.
I use TransparentDock and like others have reported, the Dock is now back to the default appearance. I don't plan to do anything until I see a new version of TD at VersionTracker. At least a couple people had problems with their Dock completely dissappearing when that attempted to modify it after the update.
I use SafarIcon to customize the menu look and it's back to default. Again, I'll wait for the SafarIcon update, or at least I'll check the developer's site for any information before I run the application.
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I just ran SafarIcon and it worked perfectly.