If you get a hosting server of your own, it will work independently, so it will have its own Operating System and you'll be able to later install server side applications directly or script-driven internet sites through a hosting Control Panel. While keeping the Operating System updated is not always considered an absolute necessity, it can be a rather important task for a variety of reasons. A newer Operating system version may have better support for specific hardware, so you might get better performance for the websites and web apps you install. Your server shall also be more safe as updates typically include security patches that fix small issues that may enable unauthorized people to access your content. Last, but not least, current script versions, which are also released for both enhanced security and for additional features, may require a later version of the Os in order to work correctly and with their full capabilities.