Check if iOS app update available

needsUpdate.m

// From https://stackoverflow.com/questions/6256748/check-if-my-app-has-a-new-version-on-appstore

-(BOOL) needsUpdate{
    NSDictionary* infoDictionary = [[NSBundle mainBundle] infoDictionary];
    NSString* appID = infoDictionary[@"CFBundleIdentifier"];
    NSURL* url = [NSURL URLWithString:[NSString stringWithFormat:@"http://itunes.apple.com/lookup?bundleId=%@", appID]];
    NSData* data = [NSData dataWithContentsOfURL:url];
    NSDictionary* lookup = [NSJSONSerialization JSONObjectWithData:data options:0 error:nil];

    if ([lookup[@"resultCount"] integerValue] == 1){
        NSString* appStoreVersion = lookup[@"results"][0][@"version"];
        NSString* currentVersion = infoDictionary[@"CFBundleShortVersionString"];
        if (![appStoreVersion isEqualToString:currentVersion]){
            NSLog(@"Need to update [%@ != %@]", appStoreVersion, currentVersion);
            return YES;
        }
    }
    return NO;
}