When planning for a system upgrade, you can opt for a clean installation or an in-place upgrade.
Red Hat provides the Leapp tool to perform in-place upgrades for RHEL systems.
Your in-place upgrade plan might reflect the requirements of your applications, the supported upgrade path, known limitations of Leapp, hardware support, and security considerations.
The system being upgraded requires access to software repositories for the source release version and the target release version. If the system does not use the standard repositories, then you can define custom software repositories.
Before upgrading your system, use the Leapp tool to run a pre-upgrade analysis and address any issues that it reports.
After the upgrade, review the output of the Leapp tool and the system logs to confirm that the upgrade completed successfully.
Some post-upgrade tasks might need to be performed manually, such as returning SELinux to enforcing mode, removing obsolete packages, and testing your application.