Parse iOS SDKでPFObjectのサブクラスを登録し忘れないようにする ref: http://qiita.com/roothybrid7/items/2eff484f1a87f0776925

new.m

// Armor.h
@interface Armor : PFObject<PFSubclassing>
+ (NSString *)parseClassName;
@end

// Armor.m
// Import this header to let Armor know that PFObject privately provides most
// of the methods for PFSubclassing.
#import <Parse/PFObject+Subclass.h>

@implementation Armor
// クラスロード時に登録を行う
+ (void)load {
    __weak typeof(self) weakSelf = self;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        [weakSelf registerSubclass];
    });
}

+ (NSString *)parseClassName {
  return @"Armor";
}
@end

// AppDelegate.m
#import <Parse/Parse.h>
//#import "Armor.h"               // これと

- (BOOL)application:(UIApplication *)application
didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
//  [Armor registerSubclass];     // これはいらない
  [Parse setApplicationId:parseAppId clientKey:parseClientKey];
}

original.m

// Armor.h
@interface Armor : PFObject<PFSubclassing>
+ (NSString *)parseClassName;
@end

// Armor.m
// Import this header to let Armor know that PFObject privately provides most
// of the methods for PFSubclassing.
#import <Parse/PFObject+Subclass.h>

@implementation Armor
+ (NSString *)parseClassName {
  return @"Armor";
}
@end

// AppDelegate.m
#import <Parse/Parse.h>
#import "Armor.h"               // これと

- (BOOL)application:(UIApplication *)application
didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
  [Armor registerSubclass];     // この箇所
  [Parse setApplicationId:parseAppId clientKey:parseClientKey];
}