MRProgressHelper.h and MRBlurView.m call +[UIApplication sharedApplication], which is not available in App Extensions, meaning that MRProgress will not compile for extension targets.
MRProgress/src/Utils/MRProgressHelper.h:41:56: 'sharedApplication' is unavailable: not available on iOS (App Extension) - Use view controller based solutions where appropriate instead.
MRProgressHelper.h
andMRBlurView.m
call+[UIApplication sharedApplication]
, which is not available in App Extensions, meaning that MRProgress will not compile for extension targets.