If you get a server of your own, it will work independently, so it'll have its own Operating System and you can later install server side programs directly or script-driven sites through a hosting Cp. Though keeping the Operating System updated is not always considered an absolute necessity, it can be a very important task for a number of reasons. A more modern Operating system version could have better support for specific hardware, so you might get better performance for the websites and web apps you install. Your server will also be more secure as updates often include security patches which resolve small problems which may enable unauthorized individuals to access your content. Last, but not least, newer script versions, which are also released for both improved security and for additional features, may need a later version of the Operating System in order to work properly and with their 100 % capabilities.