It appears to me that a standard Ubuntu 20.04 distribution needs to be updated very regularly to protect the Apache server from hacking.
As I understand it, there are several commands to do this. Each one has a dated pedigree driving its usage.
From the Ubuntu manuals:
- apt update "…is used to resynchronize the package index files from their sources."
- apt upgrade "…is used to install the newest versions of all packages currently installed on the system from the sources enumerated in /etc/apt/sources.list."
- apt-get dist-upgrade "…in addition to performing the function of upgrade, also intelligently handles changing dependencies with new versions of packages."
- apt full-upgrade NOT IN MANUAL "…performs the function of upgrade but may also remove installed packages if that is required in order to resolve a package conflict."
- apt-get autoremove "…is used to remove packages that were automatically installed to satisfy dependencies for other packages and are now no longer needed."
From another question: "By default, apt will ask you to overwrite or leave as-is, any configuration file detected to be changed during an upgrade."
But does this include "all" custom files like default, conf, ini, and other non-config-labeled files?
>Solution :
Yes: Apt should ask you about each one if it detects a difference.
However, packagers are human beings and therefore fallible. Backups of your configs are wise.
If you discover a config file that is silently overwritten, please file a bug report.