Each and every virtual or dedicated server has its own Operating System and works separately from the hosting servers of other clients. Updating the OS is frequently overlooked, but doing that could have quite a lot of advantages for your sites. The most essential reason to use the most up-to-date version is that patches are frequently released to fix security holes in the Os code, so if you don't install the updates, you risk people with harmful intentions to take advantage of these holes and to gain access to your content. Operating system updates are also released for much better performance of the system overall and for far better compatibility with the hardware available on the market, which can instantly impact the functionality of your sites. If the functionality and the security of your scripts is the reason to update them, you might also know that their newest versions require an updated Operating System to be able to operate effectively, consequently keeping the OS up-to-date is always a good idea.