If you get a server of your own, it will run independently, so it will have its own Os and you can later install server side applications directly or script-driven websites via a hosting Cp. While keeping the Operating System updated is not always considered an absolute necessity, it can be a really important task for several reasons. A newer OS version may have better support for specific hardware, so you may get better performance for the websites and web applications which you install. Your server shall also be more safe because updates usually include security patches that take care of small issues which may permit unauthorized individuals to access your content. Last, but not least, current script versions, which are also released for both increased security and for additional features, may require a later version of the Os in order to work correctly and with their full capabilities.