Each virtual or dedicated server has its own Os and operates independently from the servers of other clients. Updating the Operating system is usually overlooked, but doing that might have quite a lot of advantages for your websites. The most important reason to employ the newest version is that patches are frequently released to deal with security holes inside the Os code, so if you don't install the updates, you risk individuals with malicious intentions to exploit these holes and to get access to your content. Operating system updates are also released for improved functionality of the system as a whole and for much better compatibility with the hardware available on the market, which can instantly impact the performance of your sites. If the functionality and the security of your scripts is the reason to update them, you may also discover that their most up-to-date versions require an updated Os in order to operate properly, thus keeping the OS up-to-date is always a good idea.