Every virtual or dedicated hosting machine has its own Os and operates separately from the hosting machines of other clients. Updating the OS is usually neglected, but doing that may have lots of benefits for your internet sites. The most important reason to use the most up-to-date version is that patches are frequently released to deal with security holes within the Os code, so if you don't install the updates, you risk individuals with destructive intentions to take advantage of these holes and to gain access to your content. Operating system updates are also released for much better performance of the system in general and for much better compatibility with the hardware on the market, which can directly influence the functionality of your websites. If the functionality 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 Operating System to be able to function properly, therefore keeping the Operating system up-to-date is always a wise idea.