In app delegate delete unused method stubs except for applicationDidReceiveMemoryWarning:
Shorten pragma marks from 2 lines to 1 line.
Delete deprecated method viewDidUnload
Delete deprecated method shouldAutorotateToInterfaceOrientation:
In TrinaryTreeAppDelegate  delete declare ivar that backs property, delete @synthesize.
In Node.h delete empty braces, in .m delete @synthesize.
In TrinaryTree delete declare ivar that backs property, delete @synthesize.
In AddNodeViewController delete declare ivar that backs property, delete @synthesize.
Change method from deprecated dismissModalViewControllerAnimated to dismissViewControllerAnimated: completion:
Change method from deprecated presentModalViewController: animated: to presentViewController: animated: completion: