If you get a server of your own, it will run independently, so it'll have its own Os and you could later install server side applications directly or script-driven sites via a hosting Cp. While keeping the Os updated isn't always considered a necessity, it can be a very important task for several reasons. A newer Operating system version could have better support for certain hardware, so you could get better performance for the websites and web applications that you install. Your server shall also be more safe since updates normally include security patches which fix small problems which may permit unauthorized individuals to access your content. Last, but not least, more modern script versions, which are also released for both increased security and for additional features, may need a later version of the Operating System in order to work properly and with their full capabilities.