ios版本version识别

    NSLLog(@"system version:%@", [[UIDevice currentDevice] systemVersion]);
    
    BOOL displayLinkSupported;
    NSString *reqSysVer = @"7.0";
    NSString *currSysVer = [[UIDevice currentDevice] systemVersion];
    if ([currSysVer compare:reqSysVer options:NSNumericSearch] != NSOrderedAscending)
    {
        displayLinkSupported = TRUE;
        NSLog(@"7.0以上的iOS版本");
    }else{
        displayLinkSupported = NO;
        NSLog(@"7.0以下ios版本");
    }

参考：http://stackoverflow.com/questions/3339722/check-iphone-ios-version