We are using custom fonts in our project. It works well in Xcode 5. In Xcode 6, it works in plain text, attributed string in code. But those attributed strings set in storyboard
In case of attributed string you can add custom font in font list as - Click on font icon this will display following dialog .In the following dialog you can add your own category or existing one for custom font.attributed font dialog
After it click on Manage Fonts it open the following dialog select category in you created or existing one . Click on + sign to add font in the category. Manage font dialog