Each virtual or dedicated hosting machine has its own Operating System and functions independently from the hosting servers of other clients. Updating the OS is usually ignored, but doing that may have lots of advantages for your websites. The most important reason to employ the newest version is that patches are typically released to deal with security holes within the Os code, so if you do not install the updates, you risk people with malicious intentions to use these holes and to access your content. OS updates are also released for enhanced efficiency of the system in general and for far better compatibility with the hardware available on the market, which can instantly influence the efficiency of your websites. If the performance and the security of your scripts is the reason to update them, you might also find out that their most up-to-date versions require an updated Os to be able to function properly, so keeping the OS up-to-date is always recommended.