Each and every virtual or dedicated hosting server has its own Operating System and works independently from the hosting servers of other customers. Updating the Operating system is usually ignored, but doing that may have quite a lot of advantages for your sites. The most significant reason to employ the most recent version is that patches are frequently released to fix security holes in the Operating System code, so if you don't install the updates, you risk people with malicious intentions to exploit these holes and to access your content. Operating system updates are also released for much better performance of the system as a whole and for better compatibility with the hardware on the market, which can directly impact the efficiency of your sites. If the performance and the security of your scripts is the reason to update them, you could also know that their latest versions require an updated Os to be able to work effectively, thus keeping the OS up-to-date is always a good idea.