As mentioned earlier, Moodle HQ releases updates on a regular basis, which include bug fixes and security patches. Hence, it is important to know how to update the Moodle codebase to keep it secure.
Most importantly, any Moodle site older than 2.2 being upgraded to above 2.2 must be first upgraded to 2.2 completely, and then upgraded to 2.X.
Your first step is to create a copy of your live site and practice the upgrade process on it from the beginning to the end, ensuring that everything upgrades as expected.
These are the recommended steps to create a clone of your Moodle live site: