Try this:
Objective-C
[[UINavigationBar appearance] setTitleTextAttributes:attrsDictionary];
Swift 3
self.navigationController.navigationBar.titleTextAttributes = [NSFontAttributeName: UIFont(name: "CaviarDreams", size: 20)!]
Swift 4
self.navigationController.navigationBar.titleTextAttributes = [NSAttributedStringKey.font: UIFont(name: "CaviarDreams", size: 20)!]