Emit build warnings in Xcode 5 for methods only available on a later iOS version than the deployment target. The pch below is set to warn on methods newer than 6.1. Change the __IPHONE_6_1 part for a different version. Code taken from http://stackoverflow.com/a/8919108/412916 and http://stackoverflow.com/a/19704587/412916

availableMacrosXcode5.h

#import <Foundation/NSObjCRuntime.h>

#undef CF_AVAILABLE
#undef CF_AVAILABLE_MAC
#undef CF_AVAILABLE_IOS
#undef CF_DEPRECATED
#undef CF_DEPRECATED_MAC
#undef CF_DEPRECATED_IOS
#undef CF_ENUM_AVAILABLE
#undef CF_ENUM_AVAILABLE_MAC
#undef CF_ENUM_AVAILABLE_IOS
#undef CF_ENUM_DEPRECATED
#undef CF_ENUM_DEPRECATED_MAC
#undef CF_ENUM_DEPRECATED_IOS

#undef NS_AVAILABLE
#undef NS_AVAILABLE_MAC
#undef NS_AVAILABLE_IOS
#undef NS_DEPRECATED
#undef NS_DEPRECATED_MAC
#undef NS_DEPRECATED_IOS
#undef NS_ENUM_AVAILABLE
#undef NS_ENUM_AVAILABLE_MAC
#undef NS_ENUM_AVAILABLE_IOS
#undef NS_ENUM_DEPRECATED
#undef NS_ENUM_DEPRECATED_MAC
#undef NS_ENUM_DEPRECATED_IOS
#undef NS_AVAILABLE_IPHONE
#undef NS_DEPRECATED_IPHONE

#undef NS_CLASS_AVAILABLE
#undef NS_CLASS_DEPRECATED
#undef NS_CLASS_AVAILABLE_IOS
#undef NS_CLASS_AVAILABLE_MAC
#undef NS_CLASS_DEPRECATED_MAC
#undef NS_CLASS_DEPRECATED_IOS

//CF macros redefinition
#define CF_AVAILABLE(_mac, _ios) __OSX_AVAILABLE_STARTING(__MAC_##_mac, __IPHONE_##_ios)
#define CF_AVAILABLE_MAC(_mac) __OSX_AVAILABLE_STARTING(__MAC_##_mac, __IPHONE_NA)
#define CF_AVAILABLE_IOS(_ios) __OSX_AVAILABLE_STARTING(__MAC_NA, __IPHONE_##_ios)

#define CF_DEPRECATED(_macIntro, _macDep, _iosIntro, _iosDep, ...) __OSX_AVAILABLE_BUT_DEPRECATED(__MAC_##_macIntro, __MAC_##_macDep, __IPHONE_##_iosIntro, __IPHONE_##_iosDep)
#define CF_DEPRECATED_MAC(_macIntro, _macDep, ...) __OSX_AVAILABLE_BUT_DEPRECATED(__MAC_##_macIntro, __MAC_##_macDep, __IPHONE_NA, __IPHONE_NA)
#define CF_DEPRECATED_IOS(_iosIntro, _iosDep, ...) __OSX_AVAILABLE_BUT_DEPRECATED(__MAC_NA, __MAC_NA, __IPHONE_##_iosIntro, __IPHONE_##_iosDep)

#define CF_ENUM_AVAILABLE(_mac, _ios) CF_AVAILABLE(_mac, _ios)
#define CF_ENUM_AVAILABLE_MAC(_mac) CF_AVAILABLE_MAC(_mac)
#define CF_ENUM_AVAILABLE_IOS(_ios) CF_AVAILABLE_IOS(_ios)

#define CF_ENUM_DEPRECATED(_macIntro, _macDep, _iosIntro, _iosDep, ...) CF_DEPRECATED(_macIntro, _macDep, _iosIntro, _iosDep, __VA_ARGS__)
#define CF_ENUM_DEPRECATED_MAC(_macIntro, _macDep, ...) CF_DEPRECATED_MAC(_macIntro, _macDep, __VA_ARGS__)
#define CF_ENUM_DEPRECATED_IOS(_iosIntro, _iosDep, ...) CF_DEPRECATED_IOS(_iosIntro, _iosDep, __VA_ARGS__)

//NS macros redefinition
#define NS_AVAILABLE(_mac, _ios) CF_AVAILABLE(_mac, _ios)
#define NS_AVAILABLE_MAC(_mac) CF_AVAILABLE_MAC(_mac)
#define NS_AVAILABLE_IOS(_ios) CF_AVAILABLE_IOS(_ios)

#define NS_DEPRECATED(_macIntro, _macDep, _iosIntro, _iosDep, ...) CF_DEPRECATED(_macIntro, _macDep, _iosIntro, _iosDep, __VA_ARGS__)
#define NS_DEPRECATED_MAC(_macIntro, _macDep, ...) CF_DEPRECATED_MAC(_macIntro, _macDep, __VA_ARGS__)
#define NS_DEPRECATED_IOS(_iosIntro, _iosDep, ...) CF_DEPRECATED_IOS(_iosIntro, _iosDep, __VA_ARGS__)

#define NS_ENUM_AVAILABLE(_mac, _ios) CF_ENUM_AVAILABLE(_mac, _ios)
#define NS_ENUM_AVAILABLE_MAC(_mac) CF_ENUM_AVAILABLE_MAC(_mac)
#define NS_ENUM_AVAILABLE_IOS(_ios) CF_ENUM_AVAILABLE_IOS(_ios)

#define NS_ENUM_DEPRECATED(_macIntro, _macDep, _iosIntro, _iosDep, ...) CF_ENUM_DEPRECATED(_macIntro, _macDep, _iosIntro, _iosDep, __VA_ARGS__)
#define NS_ENUM_DEPRECATED_MAC(_macIntro, _macDep, ...) CF_ENUM_DEPRECATED_MAC(_macIntro, _macDep, __VA_ARGS__)
#define NS_ENUM_DEPRECATED_IOS(_iosIntro, _iosDep, ...) CF_ENUM_DEPRECATED_IOS(_iosIntro, _iosDep, __VA_ARGS__)

#define NS_AVAILABLE_IPHONE(_ios) CF_AVAILABLE_IOS(_ios)
#define NS_DEPRECATED_IPHONE(_iosIntro, _iosDep) CF_DEPRECATED_IOS(_iosIntro, _iosDep)

#define NS_CLASS_AVAILABLE(_mac, _ios) __attribute__((visibility("default"))) NS_AVAILABLE(_mac, _ios)
#define NS_CLASS_DEPRECATED(_mac, _macDep, _ios, _iosDep, ...) __attribute__((visibility("default"))) NS_DEPRECATED(_mac, _macDep, _ios, _iosDep, __VA_ARGS__)

#define NS_CLASS_AVAILABLE_IOS(_ios) NS_CLASS_AVAILABLE(NA, _ios)
#define NS_CLASS_AVAILABLE_MAC(_mac) NS_CLASS_AVAILABLE(_mac, NA)
#define NS_CLASS_DEPRECATED_MAC(_macIntro, _macDep, ...) NS_CLASS_DEPRECATED(_macIntro, _macDep, NA, NA, __VA_ARGS__)
#define NS_CLASS_DEPRECATED_IOS(_iosIntro, _iosDep, ...) NS_CLASS_DEPRECATED(NA, NA, _iosIntro, _iosDep, __VA_ARGS__)

MJGAvailability.h

//
//  MJGImageLoader.h
//  MJGFoundation
//
//  Created by Matt Galloway on 18/01/2012.
//  Copyright 2012 Matt Galloway. All rights reserved.
//

/**
 * Example usage:
 *   If you want to see if you're using methods that are only defined in iOS 4.0 and lower 
 *   then you would use the following. Replace the __IPHONE_4_0 with whatever other macro 
 *   you require. See Availability.h for iOS versions these relate to.
 * 
 * YourProjectPrefixHeader.pch:
 *   #define __IPHONE_OS_VERSION_SOFT_MAX_REQUIRED __IPHONE_4_0
 *   #import "MJGAvailability.h"
 *   
 *   // The rest of your prefix header as normal
 *   #import <UIKit/UIKit.h>
 * 
 * For OSX, you also get the warnings:
 * 
 * YourOSXPrefixHeader.pch
 *   #define __MAC_OS_X_VERSION_SOFT_MAX_REQUIRED __MAC_10_7
 *   #import "MJGAvailability.h"
 *
 * If you want to suppress a single warning (i.e. because you know that what you're doing is 
 * actually OK) then you can do something like this:
 *
 *   UINavigationBar *navBar = self.navigationController.navigationBar;
 *   if ([navBar respondsToSelector:@selector(setBackgroundImage:forBarMetrics:)]) {
 *   #pragma clang diagnostic push
 *   #pragma clang diagnostic ignored "-Wdeprecated-declarations"
 *       [navBar setBackgroundImage:[UIImage imageNamed:@"navbar_bg.png"] forBarMetrics:UIBarMetricsDefault];
 *   #pragma clang diagnostic pop
 *   }
 *
 * Or you can use the handy macros defined in this file also, like this:
 *
 *   UINavigationBar *navBar = self.navigationController.navigationBar;
 *   if ([navBar respondsToSelector:@selector(setBackgroundImage:forBarMetrics:)]) {
 *   MJG_START_IGNORE_TOO_NEW
 *       [navBar setBackgroundImage:[UIImage imageNamed:@"navbar_bg.png"] forBarMetrics:UIBarMetricsDefault];
 *   MJG_END_IGNORE_TOO_NEW
 *   }
 *
 */

#import <Availability.h>

#define MJG_START_IGNORE_TOO_NEW _Pragma("clang diagnostic push") _Pragma("clang diagnostic ignored \"-Wdeprecated-declarations\"")
#define MJG_END_IGNORE_TOO_NEW _Pragma("clang diagnostic pop")

#define __AVAILABILITY_TOO_NEW __attribute__((deprecated("Uses a future iOS version."))) __attribute__((weak_import))

#if defined(__IPHONE_OS_VERSION_MIN_REQUIRED)

#ifndef __IPHONE_OS_VERSION_SOFT_MAX_REQUIRED
#define __IPHONE_OS_VERSION_SOFT_MAX_REQUIRED __IPHONE_OS_VERSION_MIN_REQUIRED
#endif

#if __IPHONE_OS_VERSION_SOFT_MAX_REQUIRED < __IPHONE_OS_VERSION_MIN_REQUIRED
    #error You cannot ask for a soft max version which is less than the deployment target
#endif

#if __IPHONE_OS_VERSION_SOFT_MAX_REQUIRED < __IPHONE_2_0
    #undef __AVAILABILITY_INTERNAL__IPHONE_2_0
    #define __AVAILABILITY_INTERNAL__IPHONE_2_0 __AVAILABILITY_TOO_NEW
#endif

#if __IPHONE_OS_VERSION_SOFT_MAX_REQUIRED < __IPHONE_2_1
    #undef __AVAILABILITY_INTERNAL__IPHONE_2_1
    #define __AVAILABILITY_INTERNAL__IPHONE_2_1 __AVAILABILITY_TOO_NEW
#endif

#if __IPHONE_OS_VERSION_SOFT_MAX_REQUIRED < __IPHONE_2_2
    #undef __AVAILABILITY_INTERNAL__IPHONE_2_2
    #define __AVAILABILITY_INTERNAL__IPHONE_2_2 __AVAILABILITY_TOO_NEW
#endif

#if __IPHONE_OS_VERSION_SOFT_MAX_REQUIRED < __IPHONE_3_0
    #undef __AVAILABILITY_INTERNAL__IPHONE_3_0
    #define __AVAILABILITY_INTERNAL__IPHONE_3_0 __AVAILABILITY_TOO_NEW
#endif

#if __IPHONE_OS_VERSION_SOFT_MAX_REQUIRED < __IPHONE_3_1
    #undef __AVAILABILITY_INTERNAL__IPHONE_3_1
    #define __AVAILABILITY_INTERNAL__IPHONE_3_1 __AVAILABILITY_TOO_NEW
#endif

#if __IPHONE_OS_VERSION_SOFT_MAX_REQUIRED < __IPHONE_3_2
    #undef __AVAILABILITY_INTERNAL__IPHONE_3_2
    #define __AVAILABILITY_INTERNAL__IPHONE_3_2 __AVAILABILITY_TOO_NEW
#endif

#if __IPHONE_OS_VERSION_SOFT_MAX_REQUIRED < __IPHONE_4_0
    #undef __AVAILABILITY_INTERNAL__IPHONE_4_0
    #define __AVAILABILITY_INTERNAL__IPHONE_4_0 __AVAILABILITY_TOO_NEW
#endif

#if __IPHONE_OS_VERSION_SOFT_MAX_REQUIRED < __IPHONE_4_1
    #undef __AVAILABILITY_INTERNAL__IPHONE_4_1
    #define __AVAILABILITY_INTERNAL__IPHONE_4_1 __AVAILABILITY_TOO_NEW
#endif

#if __IPHONE_OS_VERSION_SOFT_MAX_REQUIRED < __IPHONE_4_2
    #undef __AVAILABILITY_INTERNAL__IPHONE_4_2
    #define __AVAILABILITY_INTERNAL__IPHONE_4_2 __AVAILABILITY_TOO_NEW
#endif

#if __IPHONE_OS_VERSION_SOFT_MAX_REQUIRED < __IPHONE_4_3
    #undef __AVAILABILITY_INTERNAL__IPHONE_4_3
    #define __AVAILABILITY_INTERNAL__IPHONE_4_3 __AVAILABILITY_TOO_NEW
#endif

#if __IPHONE_OS_VERSION_SOFT_MAX_REQUIRED < __IPHONE_5_0
    #undef __AVAILABILITY_INTERNAL__IPHONE_5_0
    #define __AVAILABILITY_INTERNAL__IPHONE_5_0 __AVAILABILITY_TOO_NEW
#endif

#if __IPHONE_OS_VERSION_SOFT_MAX_REQUIRED < __IPHONE_5_1
    #undef __AVAILABILITY_INTERNAL__IPHONE_5_1
    #define __AVAILABILITY_INTERNAL__IPHONE_5_1 __AVAILABILITY_TOO_NEW
#endif

#if __IPHONE_OS_VERSION_SOFT_MAX_REQUIRED < __IPHONE_6_0
    #undef __AVAILABILITY_INTERNAL__IPHONE_6_0
    #define __AVAILABILITY_INTERNAL__IPHONE_6_0 __AVAILABILITY_TOO_NEW
#endif

#if __IPHONE_OS_VERSION_SOFT_MAX_REQUIRED < __IPHONE_6_1
    #undef __AVAILABILITY_INTERNAL__IPHONE_6_1
    #define __AVAILABILITY_INTERNAL__IPHONE_6_1 __AVAILABILITY_TOO_NEW
#endif

#if __IPHONE_OS_VERSION_SOFT_MAX_REQUIRED < __IPHONE_7_0
    #undef __AVAILABILITY_INTERNAL__IPHONE_7_0
    #define __AVAILABILITY_INTERNAL__IPHONE_7_0 __AVAILABILITY_TOO_NEW
#endif

#endif // end of #if defined(__IPHONE_OS_VERSION_MIN_REQUIRED)

#if defined(__MAC_OS_X_VERSION_MIN_REQUIRED)

#ifndef __MAC_OS_X_VERSION_SOFT_MAX_REQUIRED
#define __MAC_OS_X_VERSION_SOFT_MAX_REQUIRED __MAC_OS_X_VERSION_MIN_REQUIRED
#endif

#if __MAC_OS_X_VERSION_SOFT_MAX_REQUIRED < __MAC_OS_X_VERSION_MIN_REQUIRED
#error You cannot ask for a soft max version which is less than the deployment target
#endif

#if __MAC_OS_X_VERSION_SOFT_MAX_REQUIRED < __MAC_10_0
#undef __AVAILABILITY_INTERNAL__MAC_10_0
#define __AVAILABILITY_INTERNAL__MAC_10_0 __AVAILABILITY_TOO_NEW
#endif

#if __MAC_OS_X_VERSION_SOFT_MAX_REQUIRED < __MAC_10_1
#undef __AVAILABILITY_INTERNAL__MAC_10_1
#define __AVAILABILITY_INTERNAL__MAC_10_1 __AVAILABILITY_TOO_NEW
#endif

#if __MAC_OS_X_VERSION_SOFT_MAX_REQUIRED < __MAC_10_2
#undef __AVAILABILITY_INTERNAL__MAC_10_2
#define __AVAILABILITY_INTERNAL__MAC_10_2 __AVAILABILITY_TOO_NEW
#endif

#if __MAC_OS_X_VERSION_SOFT_MAX_REQUIRED < __MAC_10_3
#undef __AVAILABILITY_INTERNAL__MAC_10_3
#define __AVAILABILITY_INTERNAL__MAC_10_3 __AVAILABILITY_TOO_NEW
#endif

#if __MAC_OS_X_VERSION_SOFT_MAX_REQUIRED < __MAC_10_4
#undef __AVAILABILITY_INTERNAL__MAC_10_4
#define __AVAILABILITY_INTERNAL__MAC_10_4 __AVAILABILITY_TOO_NEW
#endif

#if __MAC_OS_X_VERSION_SOFT_MAX_REQUIRED < __MAC_10_5
#undef __AVAILABILITY_INTERNAL__MAC_10_5
#define __AVAILABILITY_INTERNAL__MAC_10_5 __AVAILABILITY_TOO_NEW
#endif

#if __MAC_OS_X_VERSION_SOFT_MAX_REQUIRED < __MAC_10_6
#undef __AVAILABILITY_INTERNAL__MAC_10_6
#define __AVAILABILITY_INTERNAL__MAC_10_6 __AVAILABILITY_TOO_NEW
#endif

#if __MAC_OS_X_VERSION_SOFT_MAX_REQUIRED < __MAC_10_7
#undef __AVAILABILITY_INTERNAL__MAC_10_7
#define __AVAILABILITY_INTERNAL__MAC_10_7 __AVAILABILITY_TOO_NEW
#endif

#if __MAC_OS_X_VERSION_SOFT_MAX_REQUIRED < __MAC_10_8
#undef __AVAILABILITY_INTERNAL__MAC_10_8
#define __AVAILABILITY_INTERNAL__MAC_10_8 __AVAILABILITY_TOO_NEW
#endif

#endif // end of #if defined(__MAC_OS_X_VERSION_MIN_REQUIRED)

YourTarget.pch

#import <Availability.h>
#import "availableMacrosXcode5.h"
#define __IPHONE_OS_VERSION_SOFT_MAX_REQUIRED __IPHONE_6_1
#import "MJGAvailability.h"