If you get a server of your own, it will operate independently, so it'll have its own Os and you'll be able to later install server side apps directly or script-driven internet sites via a hosting Control Panel. Though keeping the Operating System updated isn't always considered a necessity, it can be a really important task for several reasons. A more modern Operating system version could have better support for certain hardware, so you could get better performance for the internet sites and web apps that you install. Your server shall also be more safe since updates often include security patches that take care of small issues that may allow unauthorized people 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 100 % capabilities.