Each virtual or dedicated hosting machine has its own Os and works separately from the hosting servers of other clients. Updating the Operating system is frequently overlooked, but doing that might have quite a lot of benefits for your sites. The most important reason to use the most up-to-date version is that patches are frequently released to repair security holes inside the Operating System code, so if you don't install the updates, you risk people with harmful intentions to take advantage of these holes and to access your content. OS updates are also released for much better efficiency of the system as a whole and for far better compatibility with the hardware available on the market, which could instantly affect the functionality of your websites. If the efficiency and the security of your scripts is the reason to update them, you could also know that their most up-to-date versions require an updated Os so as to work effectively, thus keeping the OS up-to-date is always a wise idea.