I don’t see the correlation between the two. A plugin update doesn’t open up WordPress installation to any vulnerabilities unless the plugin update itself has hacked code, which I can assure you is not the case with Jetpack.
Most typical hacks are from hacked admin passwords or database sql injections. Here’s an article that might be helpful:
https://blog.sucuri.net/2012/03/wordpress-understanding-its-true-vulnerability.html
Also, here’s how you can harden your WordPress installation to avoid future problems:
https://codex.www.ads-software.com/Hardening_WordPress
With regards to your client site, its Jetpack connection doesn’t seem to be working properly at the moment because we’re unable to access your site via cURL, which is needed in order to use Jetpack on your site.
Can you contact your host and let them know we tested the following:
1. Check for access to xmlrpc.php via browser:
https://beyondchronic.com/xmlrpc.php?for=jetpack
That test returned “XML-RPC server accepts POST requests only.” which is a valid result.
2. Check for access via cURL by running the following command from the command prompt:
curl -A “Jetpack by WordPress.com” -is -H ‘Content-Type: text/xml’ –data ‘<?xml version=”1.0″?><methodCall><methodName>demo.sayHello</methodName><params></params></methodCall>’ ‘https://beyondchronic.com/xmlrpc.php?for=jetpack’ && echo
The cURL test returned the following invalid result:
HTTP/1.1 403 Forbidden
Date: Thu, 10 Mar 2016 23:19:54 GMT
Content-Type: text/html; charset=UTF-8
Transfer-Encoding: chunked
Connection: keep-alive
Set-Cookie: __cfduid=d6fc5b55e1592affefd481b6b3ee4c5a21457651994; expires=Fri, 10-Mar-17 23:19:54 GMT; path=/; domain=.beyondchronic.com; HttpOnly
Cache-Control: max-age=15
Expires: Thu, 10 Mar 2016 23:20:09 GMT
X-Frame-Options: SAMEORIGIN
Server: cloudflare-nginx
CF-RAY: 281a7e82a3ae2a4f-SEA
Please provide the information above to your hosting provider so that they can correct the server settings to allow cURL access.
Let me know if you have any questions.