NSString *deviceType = [[UIDevice currentDevice] systemName];

我可以保证，上述建议将适用于iOS 7及以上版本。我相信iOS 6也能运行。但我不确定。

NSString *deviceType = [UIDevice currentDevice].model;

要识别iPhone 4S，只需检查以下内容:

var isIphone4S: Bool {

    let width = UIScreen.main.bounds.size.width
    let height = UIScreen.main.bounds.size.height
    let proportions = width > height ? width / height : height / width

    return proportions == 1.5 && UIDevice.current.model == "iPhone"
}

以下是新模型的小更新:

- (NSString *) platformString{
    NSString *platform = [self platform];
    if ([platform isEqualToString:@"iPhone1,1"]) return @"iPhone 1G";
    if ([platform isEqualToString:@"iPhone1,2"]) return @"iPhone 3G";
    if ([platform isEqualToString:@"iPhone2,1"]) return @"iPhone 3GS";
    if ([platform isEqualToString:@"iPhone3,1"]) return @"iPhone 4";
    if ([platform isEqualToString:@"iPod1,1"])   return @"iPod Touch 1G";
    if ([platform isEqualToString:@"iPod2,1"])   return @"iPod Touch 2G";
    if ([platform isEqualToString:@"iPod3,1"])   return @"iPod Touch 3G";
    if ([platform isEqualToString:@"i386"])   return @"iPhone Simulator";
    return platform;
}

#import <sys/utsname.h> 

NSString *iPhone = [self iPhoneVersion]; 

-(NSString*)iPhoneVersion
{
   NSString *platform;
   struct utsname systemInfo;
   uname(&systemInfo);
   platform = [NSString stringWithCString:systemInfo.machine encoding:NSUTF8StringEncoding];

   if ([platform isEqualToString:@"iPhone1,1"])    return @"iPhone 1G";
   if ([platform isEqualToString:@"iPhone1,2"])    return @"iPhone 3G";
   if ([platform isEqualToString:@"iPhone2,1"])    return @"iPhone 3GS";
   if ([platform isEqualToString:@"iPhone3,1"])    return @"iPhone 4";
   if ([platform isEqualToString:@"iPhone3,3"])    return @"VerizoniPhone 4";
   if ([platform isEqualToString:@"iPhone4,1"])    return @"iPhone 4S";
   if ([platform isEqualToString:@"iPhone5,1"])    return @"iPhone 5 (GSM)";
   if ([platform isEqualToString:@"iPhone5,2"])    return @"iPhone 5 (GSM+CDMA)";
   if ([platform isEqualToString:@"iPhone5,3"])    return @"iPhone 5c (GSM)";
   if ([platform isEqualToString:@"iPhone5,4"])    return @"iPhone 5c (GSM+CDMA)";
   if ([platform isEqualToString:@"iPhone6,1"])    return @"iPhone 5s (GSM)";
   if ([platform isEqualToString:@"iPhone6,2"])    return @"iPhone 5s (GSM+CDMA)";
   if ([platform isEqualToString:@"iPhone7,2"])    return @"iPhone 6";
   if ([platform isEqualToString:@"iPhone7,1"])    return @"iPhone 6 Plus";
   if ([platform isEqualToString:@"iPod1,1"])      return @"iPod Touch 1G";
   if ([platform isEqualToString:@"iPod2,1"])      return @"iPod Touch 2G";
   if ([platform isEqualToString:@"iPod3,1"])      return @"iPod Touch 3G";
   if ([platform isEqualToString:@"iPod4,1"])      return @"iPod Touch 4G";
   if ([platform isEqualToString:@"iPod5,1"])      return @"iPod Touch 5G";
   if ([platform isEqualToString:@"iPad1,1"])      return @"iPad";
   if ([platform isEqualToString:@"iPad2,1"])      return @"iPad 2 (WiFi)";
   if ([platform isEqualToString:@"iPad2,2"])      return @"iPad 2 (GSM)";
   if ([platform isEqualToString:@"iPad2,3"])      return @"iPad 2 (CDMA)";
   if ([platform isEqualToString:@"iPad2,4"])      return @"iPad 2 (WiFi)";
   if ([platform isEqualToString:@"iPad2,5"])      return @"iPad Mini (WiFi)";
   if ([platform isEqualToString:@"iPad2,6"])      return @"iPad Mini (GSM)";
   if ([platform isEqualToString:@"iPad2,7"])      return @"iPad Mini (GSM+CDMA)";
   if ([platform isEqualToString:@"iPad3,1"])      return @"iPad 3 (WiFi)";
   if ([platform isEqualToString:@"iPad3,2"])      return @"iPad 3 (GSM+CDMA)";
   if ([platform isEqualToString:@"iPad3,3"])      return @"iPad 3 (GSM)";
   if ([platform isEqualToString:@"iPad3,4"])      return @"iPad 4 (WiFi)";
   if ([platform isEqualToString:@"iPad3,5"])      return @"iPad 4 (GSM)";
   if ([platform isEqualToString:@"iPad3,6"])      return @"iPad 4 (GSM+CDMA)";
   if ([platform isEqualToString:@"iPad4,1"])      return @"iPad Air (WiFi)";
   if ([platform isEqualToString:@"iPad4,2"])      return @"iPad Air (Cellular)";
   if ([platform isEqualToString:@"iPad4,3"])      return @"iPad Air";
   if ([platform isEqualToString:@"iPad4,4"])      return @"iPad Mini 2G (WiFi)";
   if ([platform isEqualToString:@"iPad4,5"])      return @"iPad Mini 2G (Cellular)";
   if ([platform isEqualToString:@"iPad4,6"])      return @"iPad Mini 2G";
   if ([platform isEqualToString:@"iPad4,7"])      return @"iPad Mini 3 (WiFi)";
   if ([platform isEqualToString:@"iPad4,8"])      return @"iPad Mini 3 (Cellular)";
   if ([platform isEqualToString:@"iPad4,9"])      return @"iPad Mini 3 (China)";
   if ([platform isEqualToString:@"iPad5,3"])      return @"iPad Air 2 (WiFi)";
   if ([platform isEqualToString:@"iPad5,4"])      return @"iPad Air 2 (Cellular)";
   if ([platform isEqualToString:@"AppleTV2,1"])   return @"Apple TV 2G";
   if ([platform isEqualToString:@"AppleTV3,1"])   return @"Apple TV 3";
   if ([platform isEqualToString:@"AppleTV3,2"])   return @"Apple TV 3 (2013)";
   if ([platform isEqualToString:@"i386"])         return @"Simulator";
   if ([platform isEqualToString:@"x86_64"])       return @"Simulator";
   return platform;
}

Dutchie432和Brian Robbins提供了很好的解决方案。但还有一款型号没有推出，那就是Verizon的iPhone 4。这是缺失的一行。

if ([platform isEqualToString:@"iPhone3,2"])    return @"iPhone 4"; //Verizon