Chapter 1. Preface

This document provides an overview of differences between two major versions of Red Hat Enterprise Linux: RHEL 8 and RHEL 9. It provides a list of changes relevant for evaluating an upgrade to RHEL 9 rather than an exhaustive list of all alterations.

For details regarding RHEL 9 usage, see the RHEL 9 product documentation.

For guidance regarding an in-place upgrade from RHEL 8 to RHEL 9, see Upgrading from RHEL 8 to RHEL 9.

For information about major differences between RHEL 7 and RHEL 8, see Considerations in adopting RHEL 8.

Capabilities and limits of Red Hat Enterprise Linux 9 as compared to other versions of the system are available in the Knowledgebase article Red Hat Enterprise Linux technology capabilities and limits.

Information regarding the Red Hat Enterprise Linux life cycle is provided in the Red Hat Enterprise Linux Life Cycle document.

The Package manifest document provides a package listing for RHEL 9, including licenses and application compatibility levels.

Application compatibility levels are explained in the Red Hat Enterprise Linux 9: Application Compatibility Guide document.