You should not use this anymore.

[blacklee]

Message below is copied from [iTunes Connect] Resolution Center

Rejected
Apple
Jan 20, 2014 09:51 AM
Reasons

2.5: Apps that use non-public APIs will be rejected
2.5

We found that your app interacts with the organization and layout of a provided view's internal hierarchy, which is a private entity. Interacting with private entities is not in compliance with the App Store Review Guidelines.

Specifically, your app uses classes like AMBlurView or MDBlurView, which take layers from UIToolbar and UINavigationBar view hierarchies.

Selecting specific layers or subviews in our provided views makes assumptions about the organization and layout of the view hierarchy. However, this hierarchy could change without notice, affecting the behavior of your app.

Please revise your app to remove this functionality.

[dimitribouniol]

I imagine this is easily obfuscated by placing the following to the top of your .pch file:

#define MDBlurView CheeseSandwichView
#define MDBlurLuminosity CheeseSandwichLuminosity
#define MDBlurLuminosityAutomatic CheeseSandwichLuminosityAutomatic
#define MDBlurLuminosityBright CheeseSandwichLuminosityBright
#define MDBlurLuminosityDark CheeseSandwichLuminosityDark

#define blurFraction cheeseSandwichFraction
#define blurRadius cheeseSandwichRadius
#define blurLuminosity cheeseSandwichLuminosity
#define _blurFraction _cheeseSandwichFraction
#define _blurRadius _cheeseSandwichRadius
#define _blurLuminosity _cheeseSandwichLuminosity
#define setBlurFraction setCheeseSandwichFraction
#define setBlurRadius setCheeseSandwichRadius
#define setBlurLuminosity setCheeseSandwichLuminosity

… or whatever other word you can think of. You can do the same for method names that include blur in them.

[dimitribouniol]

I can confirm that this method works, and will now close the issue. More info.