If you get a server of your own, it will operate independently, so it'll have its own Operating System and you'll be able to later install server side applications directly or script-driven websites via a hosting Cp. Although keeping the Operating System updated is not always considered an absolute necessity, it can be a quite important task for several reasons. A more modern OS version could have better support for specific hardware, so you could get better performance for the sites and web applications that you install. Your server will also be more protected as updates normally include security patches which resolve small problems that may enable unauthorized people to access your content. Last, but not least, newer script versions, which are also released for both enhanced security and for additional features, might require a later version of the Operating System in order to work properly and with their 100 % capabilities.