这个代码怎么样，如果新版本发布，你将标识与最后知道的设备

- (NSString *)getModel {
    size_t size;
    sysctlbyname("hw.machine", NULL, &size, NULL, 0);
    char *model = malloc(size);
    sysctlbyname("hw.machine", model, &size, NULL, 0);
    NSString *sDeviceModel = [NSString stringWithCString:model encoding:NSUTF8StringEncoding];
    free(model);                              
    if ([sDeviceModel isEqual:@"i386"])      return @"Simulator";  //iPhone Simulator
    if ([sDeviceModel isEqual:@"iPhone1,1"]) return @"iPhone1G";   //iPhone 1G
    if ([sDeviceModel isEqual:@"iPhone1,2"]) return @"iPhone3G";   //iPhone 3G
    if ([sDeviceModel isEqual:@"iPhone2,1"]) return @"iPhone3GS";  //iPhone 3GS
    if ([sDeviceModel isEqual:@"iPhone3,1"]) return @"iPhone3GS";  //iPhone 4 - AT&T
    if ([sDeviceModel isEqual:@"iPhone3,2"]) return @"iPhone3GS";  //iPhone 4 - Other carrier
    if ([sDeviceModel isEqual:@"iPhone3,3"]) return @"iPhone4";    //iPhone 4 - Other carrier
    if ([sDeviceModel isEqual:@"iPhone4,1"]) return @"iPhone4S";   //iPhone 4S
    if ([sDeviceModel isEqual:@"iPod1,1"])   return @"iPod1stGen"; //iPod Touch 1G
    if ([sDeviceModel isEqual:@"iPod2,1"])   return @"iPod2ndGen"; //iPod Touch 2G
    if ([sDeviceModel isEqual:@"iPod3,1"])   return @"iPod3rdGen"; //iPod Touch 3G
    if ([sDeviceModel isEqual:@"iPod4,1"])   return @"iPod4thGen"; //iPod Touch 4G
    if ([sDeviceModel isEqual:@"iPad1,1"])   return @"iPadWiFi";   //iPad Wifi
    if ([sDeviceModel isEqual:@"iPad1,2"])   return @"iPad3G";     //iPad 3G
    if ([sDeviceModel isEqual:@"iPad2,1"])   return @"iPad2";      //iPad 2 (WiFi)
    if ([sDeviceModel isEqual:@"iPad2,2"])   return @"iPad2";      //iPad 2 (GSM)
    if ([sDeviceModel isEqual:@"iPad2,3"])   return @"iPad2";      //iPad 2 (CDMA)

    NSString *aux = [[sDeviceModel componentsSeparatedByString:@","] objectAtIndex:0];

//If a newer version exist
    if ([aux rangeOfString:@"iPhone"].location!=NSNotFound) {
        int version = [[aux stringByReplacingOccurrencesOfString:@"iPhone" withString:@""] intValue];
        if (version == 3) return @"iPhone4"
        if (version >= 4) return @"iPhone4s";

    }
    if ([aux rangeOfString:@"iPod"].location!=NSNotFound) {
        int version = [[aux stringByReplacingOccurrencesOfString:@"iPod" withString:@""] intValue];
        if (version >=4) return @"iPod4thGen";
    }
    if ([aux rangeOfString:@"iPad"].location!=NSNotFound) {
        int version = [[aux stringByReplacingOccurrencesOfString:@"iPad" withString:@""] intValue];
        if (version ==1) return @"iPad3G";
        if (version >=2) return @"iPad2";
    }
    //If none was found, send the original string
    return sDeviceModel;
}

回答在Swift 3，

struct DeviceInformation {
    // UIDevice.current.model's value is "iPhone" or "iPad"，which does not include details; the following "model" is detailed, such as, iPhone7,1 is actually iPhone 6 plus
    static let model: String = {
        var size = 0
        sysctlbyname("hw.machine", nil, &size, nil, 0)
        var machine = [CChar](repeating: 0,  count: Int(size))
        sysctlbyname("hw.machine", &machine, &size, nil, 0)
        return String(cString: machine)
    }()

    static let uuid = UIDevice.current.identifierForVendor?.uuidString ?? ""
    static let idForAdService = ASIdentifierManager.shared().advertisingIdentifier.uuidString

    static func diviceTypeReadableName() -> String {
        switch model {
        case "iPhone1,1":   return "iPhone 1G"
        case "iPhone1,2":   return "iPhone 3G"
        case "iPhone2,1":   return "iPhone 3GS"
        case "iPhone3,1":   return "iPhone 4"
        case "iPhone3,3":   return "iPhone 4 (Verizon)"
        case "iPhone4,1":   return "iPhone 4S"
        case "iPhone5,1":   return "iPhone 5 (GSM)"
        case "iPhone5,2":   return "iPhone 5 (GSM+CDMA)"
        case "iPhone5,3":   return "iPhone 5c (GSM)"
        case "iPhone5,4":   return "iPhone 5c (GSM+CDMA)"
        case "iPhone6,1":   return "iPhone 5s (GSM)"
        case "iPhone6,2":   return "iPhone 5s (GSM+CDMA)"
        case "iPhone7,2":   return "iPhone 6"
        case "iPhone7,1":   return "iPhone 6 Plus"
        case "iPhone8,1":   return "iPhone 6s"
        case "iPhone8,2":   return "iPhone 6s Plus"
        case "iPhone8,4":   return "iPhone SE"
        case "iPhone9,1":   return "iPhone 7"
        case "iPhone9,3":   return "iPhone 7"
        case "iPhone9,2":   return "iPhone 7 Plus"
        case "iPhone9,4":   return "iPhone 7 Plus"
        case "iPod1,1":     return "iPod Touch 1G"
        case "iPod2,1":     return "iPod Touch 2G"
        case "iPod3,1":     return "iPod Touch 3G"
        case "iPod4,1":     return "iPod Touch 4G"
        case "iPod5,1":     return "iPod Touch 5G"
        case "iPod7,1":     return "iPod Touch 6G"
        case "iPad1,1":     return "iPad 1G"
        case "iPad2,1":     return "iPad 2 (Wi-Fi)"
        case "iPad2,2":     return "iPad 2 (GSM)"
        case "iPad2,3":     return "iPad 2 (CDMA)"
        case "iPad2,4":     return "iPad 2 (Wi-Fi)"
        case "iPad2,5":     return "iPad Mini (Wi-Fi)"
        case "iPad2,6":     return "iPad Mini (GSM)"
        case "iPad2,7":     return "iPad Mini (GSM+CDMA)"
        case "iPad3,1":     return "iPad 3 (Wi-Fi)"
        case "iPad3,2":     return "iPad 3 (GSM+CDMA)"
        case "iPad3,3":     return "iPad 3 (GSM)"
        case "iPad3,4":     return "iPad 4 (Wi-Fi)"
        case "iPad3,5":     return "iPad 4 (GSM)"
        case "iPad3,6":     return "iPad 4 (GSM+CDMA)"
        case "iPad4,1":     return "iPad Air (Wi-Fi)"
        case "iPad4,2":     return "iPad Air (Cellular)"
        case "iPad4,3":     return "iPad Air (China)"
        case "iPad4,4":     return "iPad Mini 2G (Wi-Fi)"
        case "iPad4,5":     return "iPad Mini 2G (Cellular)"
        case "iPad4,6":     return "iPad Mini 2G (China)"
        case "iPad4,7":     return "iPad Mini 3 (Wi-Fi)"
        case "iPad4,8":     return "iPad Mini 3 (Cellular)"
        case "iPad4,9":     return "iPad Mini 3 (China)"
        case "iPad5,1":     return "iPad Mini 4 (Wi-Fi)"
        case "iPad5,2":     return "iPad Mini 4 (Cellular)"
        case "iPad5,3":     return "iPad Air 2 (Wi-Fi)"
        case "iPad5,4":     return "iPad Air 2 (Cellular)"
        case "iPad6,3":     return "iPad Pro 9.7' (Wi-Fi)"
        case "iPad6,4":     return "iPad Pro 9.7' (Cellular)"
        case "iPad6,7":     return "iPad Pro 12.9' (Wi-Fi)"
        case "iPad6,8":     return "iPad Pro 12.9' (Cellular)"
        case "AppleTV2,1":  return "Apple TV 2G"
        case "AppleTV3,1":  return "Apple TV 3"
        case "AppleTV3,2":  return "Apple TV 3 (2013)"
        case "AppleTV5,3":  return "Apple TV 4"
        case "Watch1,1":    return "Apple Watch Series 1 (38mm, S1)"
        case "Watch1,2":    return "Apple Watch Series 1 (42mm, S1)"
        case "Watch2,6":    return "Apple Watch Series 1 (38mm, S1P)"
        case "Watch2,7":    return "Apple Watch Series 1 (42mm, S1P)"
        case "Watch2,3":    return "Apple Watch Series 2 (38mm, S2)"
        case "Watch2,4":    return "Apple Watch Series 2 (42mm, S2)"
        case "i386":        return "Simulator"
        case "x86_64":      return "Simulator"

        default:
            return ""
        }
    }
}

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"
}

你可以像这样使用UIDevice类:

NSString *deviceType = [UIDevice currentDevice].model;

if([deviceType isEqualToString:@"iPhone"])
    // it's an iPhone

- (BOOL)deviceiPhoneOriPod
  {
    NSString *deviceType = [UIDevice currentDevice].model;
    if([deviceType rangeOfString:@"iPhone"].location!=NSNotFound)
      return YES;
    else
      return NO;
  }

更有用

#include <sys/types.h>
#include <sys/sysctl.h>

@interface UIDevice(Hardware)

- (NSString *) platform;

- (BOOL)hasRetinaDisplay;

- (BOOL)hasMultitasking;

- (BOOL)hasCamera;

@end

@implementation UIDevice(Hardware)

- (NSString *) platform{
    int mib[2];
size_t len;
char *machine;

mib[0] = CTL_HW;
mib[1] = HW_MACHINE;
sysctl(mib, 2, NULL, &len, NULL, 0);
machine = malloc(len);
sysctl(mib, 2, machine, &len, NULL, 0);

    NSString *platform = [NSString stringWithCString:machine encoding:NSASCIIStringEncoding];
    free(machine);
return platform;
}

- (BOOL)hasRetinaDisplay {
    NSString *platform = [self platform];
    BOOL ret = YES;
    if ([platform isEqualToString:@"iPhone1,1"]) {
        ret = NO;
    }
    else
        if ([platform isEqualToString:@"iPhone1,2"])    ret = NO;
    else 
        if ([platform isEqualToString:@"iPhone2,1"])    ret = NO;
    else 
        if ([platform isEqualToString:@"iPod1,1"])      ret = NO;
    else
        if ([platform isEqualToString:@"iPod2,1"])      ret = NO;
    else
        if ([platform isEqualToString:@"iPod3,1"])      ret = NO;
    return ret;
}

- (BOOL)hasMultitasking {
    if ([self respondsToSelector:@selector(isMultitaskingSupported)]) {
        return [self isMultitaskingSupported];
    }
    return NO;
}

- (BOOL)hasCamera {
   BOOL ret = NO;
   // check camera availability
   return ret;
}

@end

您可以读取属性

NSLog(@"platform %@, retita %@, multitasking %@", [[UIDevice currentDevice] platform], [[UIDevice currentDevice] hasRetinaDisplay] ? @"YES" : @"NO" , [[UIDevice currentDevice] hasMultitasking] ? @"YES" : @"NO");