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