Generally you just install the newer version. Then you need to either call it explicitly, or change your system/account defaults to choose it first if that's what you want.
If you're on windows, the installer will probably prompt you to add it to the system PATH. For linux, you'll probably want to put it in your account's login files.
It's not a good idea to remove an older version if it came with the operating system. OS tools may be depending on that particular version. Better to just install a new one and use the new one.
