读取系统版本信息 info.plist里面的信息

 NSDictionary *dictBundle = [[NSBundle mainBundle] infoDictionary];

读取appid：

[dictBundle objectForKey:@"CFBundleIdentifier"],

读取版本号：

[dictBundle objectForKey:@"CFBundleVersion"]];

引导用户更新app：

NSDictionary *dictInfo = [[NSUserDefaults standardUserDefaults] objectForKey:TOKEN_INFO];
            [[UIApplication sharedApplication] openURL:[NSURL URLWithString:
                                                        [dictInfo objectForKey:@"ipaUrl"]]];