iOS change navigation bar title font and color

The correct way to change the title font (and color) is:

[self.navigationController.navigationBar setTitleTextAttributes:
 @{NSForegroundColorAttributeName:[UIColor redColor],
NSFontAttributeName:[UIFont fontWithName:@"mplus-1c-regular" size:21]}];

Edit: Swift 4.2

self.navigationController?.navigationBar.titleTextAttributes =
[NSAttributedString.Key.foregroundColor: UIColor.red,
 NSAttributedString.Key.font: UIFont(name: "mplus-1c-regular", size: 21)!]

Edit: Swift 4

self.navigationController?.navigationBar.titleTextAttributes =
[NSAttributedStringKey.foregroundColor: UIColor.red,
 NSAttributedStringKey.font: UIFont(name: "mplus-1c-regular", size: 21)!]

Swift 3:

self.navigationController?.navigationBar.titleTextAttributes = 
[NSForegroundColorAttributeName: UIColor.redColor(),
 NSFontAttributeName: UIFont(name: "mplus-1c-regular", size: 21)!]

Swift 5:

navigation.navigationBar.titleTextAttributes = [
    .foregroundColor: UIColor.red,
    .font: UIFont(name: "mplus-1c-regular", size: 21)!
]