Sucuri sitecheck detects Cpanel Outdated

It depends, it might be important. As we’re the WordPress support forums and not the cPanel support forums, it’s hard to offer any official advice on the matter. 😉

With that said, Sucuri usually knows what they’re doing, and if they report an outdated cPanel, it’s probably because it has one or more know security vulnerabilities, and you should probably ask your hosting provider why they haven’t bothered to upgrade it.