How do I backup local modifications or custom code that I made before installing a new update? Every time I install a new update, the custom code that I put, disappears. How do I install a new update and not make the custom code disappear or bring it back after installing the new update?
If you changed core files. please go to Administration -> File changes detector page to see list of changed files
I checked and there are two files with local modifications. Should I just install the new update or how can I backup the two files with the local modifications, before installing the new update?
Make a backup just in case. For example, us File manager in the control panel of your server