The Framework is updated regulary as new features are added and bugs are fixed. To find out if you need to update your code, login as a site administrator and select the “Update” option on the Admin menu. This will tell you if your software is up to date or not. It will also update the essential any of the essential support software versions in your database if neccessary. If there is any software that you do not want updated, then go to the “Config” menu item on the Admin menu and mark that item as Local. This will prevent it from being automatically updated.
If you have cloned the Framework from git then doing a git pull will update your code to the latest version. Watch out for merge collisions if you have chaged any of the Framework files.
If you are using the Docker version then you you need to cd into www in the directory you created to do the git pull. See the docker section on the installation page for some docker commands that you might find helpful — if you do not have git installed then you will have to run a shell in your container and use git in there after having done cd /var/www/html
If you got the code some other way then you are on your own…