Each and every virtual or dedicated hosting machine has its own Os and operates independently from the hosting machines of other customers. Updating the OS is often neglected, but doing that might have quite a lot of advantages for your sites. The most significant reason to use the most up-to-date version is that patches are typically released to repair security holes within the Os code, so if you do not install the updates, you risk people with harmful intentions to take advantage of these holes and to get access to your content. OS updates are also released for much better efficiency of the system overall and for far better compatibility with the hardware available on the market, which could instantly impact 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 newest versions require an updated Os so as to work properly, thus keeping the OS up-to-date is always a wise idea.