All based on personal experience

Sharepoint 2013 is all based around apps and azure. To be honest if you know the Client Object Model, then brush up on the 2013 and how to make an app and you are away. But it is a very different way of thinking for a 2003~2010 developer.

Still do the training though if you can, it is more than worth it. There are so many many new tricks and treats in store, you really don't want to miss anything.