Upgrade GNU/Linux Fedora from 21/22 to 23 (with dnf)

Like explained in this article, FEDora UPgrader (fedup) is deprecated since Fedora 21, where DNF system upgrade plugin became the recommended method to upgrade Fedora.

This article will explain how to use dnf with its system upgrade plugin, to Upgrade from Fedora 22 to

Fedora 23 (these instructions should be OK to upgrade from Fedora 21).

Although the Upgrade process is more and more safe, thanks to advanced tools like dnf, first of all, back up all your important data.

Like before every upgrade, don't forget to import (and check !) the GPG key of the target distribution:
 - for Fedora repositories, check this page
 - for RPM Fusion repositories, check this one

As usual, you should disable the graphical mode during the upgrade process to avoid some issues:

systemctl set-default multi-user.target

Update your current Fedora installation (the --refresh option forced the metadata update)

dnf update --refresh

If it's not already the case, install the system upgrade plugin of DNF

dnf install dnf-plugin-system-upgrade

Start the Upgrade preparation, requesting the download of target Distribution version packages (adapt the release version to your needs)

dnf system-upgrade download --releasever=23

If ever you have dependencies issues, you MUST resolve them before keeping on.

For instance, it can happen with third-party repositories' packages, for which you may consider to temporary remove them, and then reinstall them in target Distribution.

It can happen with packages which are now in conflict (like mariadb which replaced mysql-server package).

You can now request the real upgrade process

dnf system-upgrade reboot

The system will reboot on the same Kernel, and then start the Upgrade process.

Before rebooting, you should ensure system is OK.

To check the services which failed to start:

systemctl --failed

To get status of specific failing service (e.g. kdump):

systemctl status kdump

To get full log with enhanced information:

journalctl -x

Ensure, there is no dependencies problem.

And like usual, check and merge the new configuration files with 'rpmnew' suffix (which can now easily be performed with rpmconf tool).

After having fixed everything, you can switch back to graphical mode as default:

systemctl set-default graphical.target

Finally reboot and enjoy your upgraded Fedora.

N.B.: you can check this article to get some screenshots about the whole Upgrade Process with DNF.