The recommended and safest way to upgrade Fedora 21 to Fedora 23 is with the DNF system-upgrade plugin. While we try to bring all latest and greatest images/templates to our VPS services, you might still sometimes find a slightly outdated versions of OS Templates installed. Run these commands in sequence: update the base system and reboot, install DNF plus the upgrade plugin, download the release 23 packages, then reboot to apply the upgrade. This process, endorsed by the Fedora Project, handles dependency resolution and performs the change in a single offline transaction.

Upgrades matter because they deliver critical security fixes, bug corrections, and performance improvements absent in older releases. Performing the transition with the dedicated plugin reduces the chance of a partially updated system that fails to boot. The final reboot typically completes in about five minutes; monitor via console where possible.

#Prerequisites

  • Current full backup or snapshot of the VPS – upgrades carry inherent risk of data loss if conflicts arise.
  • Root SSH or console access with stable network connectivity.
  • Minimum 2 GB free disk space and 1 GB RAM available to handle package downloads and the upgrade transaction.

#Step-by-Step Instructions

#Update Current System

Bring all current packages up to date first. This step eliminates many dependency problems that could appear when jumping two major versions. The && reboot ensures kernel updates and other changes are active before proceeding.

bash 
yum update -y && reboot

#Install DNF and Plugin

After the reboot, install DNF (the next-generation replacement for YUM) and the system-upgrade plugin. These are required for the remaining commands.

bash 
yum install dnf dnf-plugin-system-upgrade -y

#Download Fedora 23 Packages

This command resolves and downloads every RPM needed for release 23 without installing them yet. Use of --releasever=23 tells the system the target version; the download may take several minutes depending on mirror speed and installed package count. Watch for errors about missing repositories or insufficient space.

bash 
dnf system-upgrade download --releasever=23 -y

#Reboot to Perform Upgrade

The final command prepares the boot environment and restarts the server. All changes occur during this boot; avoid interrupting power or network.

bash 
dnf system-upgrade reboot

Note that it might take about 5 minutes for this restart to complete. Once the system is restarted and you get your ping back, login to your new and updated Fedora 23. Common pitfalls include transient mirror failures (retry the download step) or third-party repositories that no longer support version 23 (disable them beforehand).

#Post-Upgrade Tasks

It's time to get to know new DNF package manager; familiar commands include dnf update, dnf install, and dnf remove. Verify success with cat /etc/fedora-release. Review /var/log/dnf.log for any warnings. For more details about upgrade on Fedora Project Wiki, consult the official upgrading guide. Practical takeaway: schedule future upgrades promptly after new releases, keep backups current, and test application functionality immediately after login to catch configuration adjustments required by the new version.