Having a way to easily synchronize your AdBlock settings and custom filters across the various browsers and devices you use is a great idea. We thought we could use Dropbox to do that. We kept it as a beta feature because it never quite worked out as well as we hoped. Now we have decided it's time to evaluate other methods. We will remove Dropbox sync from AdBlock after March 10, 2016.
What do you need to know?
The most important thing you need to know is that if you used Dropbox sync, you won't lose any of your data. All of your settings and custom filters are right where they always were, safely stored in the extension.
The second thing you need to know is that you won't have to do anything. The Dropbox sync feature just won't be there anymore, kind of like that last piece of chocolate cake in the fridge.