Upgrade from itms service.

itmsUpgrade.m

[[[NSURLSession sharedSession] downloadTaskWithURL:[NSURL URLWithString:@"https://alpha.migufun.com:38081/alpha/manifest.plist"] completionHandler:^(NSURL * _Nullable location, NSURLResponse * _Nullable response, NSError * _Nullable error) {
        NSDictionary *plist = [[NSDictionary alloc] initWithContentsOfURL:location];
        NSString *version = plist[@"items"][0][@"metadata"][@"bundle-version"];
        
        NSString *currentVersion = [NSBundle mainBundle].infoDictionary[@"CFBundleShortVersionString"];
        if ([version compare:currentVersion options:NSNumericSearch] == NSOrderedDescending) {
            // 需要升级
            NSURL *url = [NSURL URLWithString:@"itms-services://?action=download-manifest&url=https://alpha.migufun.com:38081/alpha/manifest.plist"];
            dispatch_async(dispatch_get_main_queue(), ^{
                [[UIApplication sharedApplication] openURL:url];
                exit(0);
            });
        }
    }] resume];