Re: Upgrading from 1.2.8 to 1.6.1 via 1.5.6?
You ought to be able to upgrade from recent 1.2.x versions up to 1.6.x without problem. Probably counts as a bug if it’s not possible. As some others have said, it’s normally theme or plugin compatibility that you have to watch out for. If you’ve got a staging or test environment, try on there and see what happens 
