Each and every virtual or dedicated hosting server has its own Os and works separately from the hosting machines of other customers. Updating the Operating system is often neglected, but doing that might have quite a lot of advantages for your sites. The most important reason to use the most recent version is that patches are frequently released to deal with security holes inside the Operating System code, so if you don't install the updates, you risk people with malicious intentions to use these holes and to gain access to your content. Operating system updates are also released for much better functionality of the system as a whole and for much better compatibility with the hardware on the market, which can instantly affect the performance of your websites. If the efficiency and the security of your scripts is the reason to update them, you might also know that their latest versions require an updated Os so as to operate properly, so keeping the OS up-to-date is always a good idea.