Chapter 1. Overview

1.1. Major changes in RHEL 9.5

Security

The OpenSSL TLS toolkit is upgraded to version 3.2.2. OpenSSL now supports certificate compression extension (RFC 8879) and Brainpool curves have been added to the TLS 1.3 protocol (RFC 8734).

The ca-certificates program now provides trusted CA roots in the OpenSSL directory format.

The crypto-policies packages have been updated to extend its control to algorithm selection in Java.

The SELinux policy now provides a boolean that allows QEMU Guest Agent to execute confined commands.

The NSS cryptographic toolkit packages have been rebased to upstream version 3.101.

See New features - Security for more information.

Dynamic programming languages, web and database servers

Later versions of the following Application Streams are now available:

Apache HTTP Server 2.4.62
Node.js 22

See New features - Dynamic programming languages, web and database servers and Technology Previews - Dynamic programming languages, web and database servers for more information.

Compilers and development tools

Updated system toolchain

The following system toolchain components have been updated:

GCC 11.5
Annobin 12.70

Updated performance tools and debuggers

The following performance tools and debuggers have been updated in RHEL 9.5:

GDB 14.2
Valgrind 3.23.0
SystemTap 5.1
elfutils 0.191
libabigail 2.5

Updated performance monitoring tools

The following performance monitoring tools have been updated in RHEL 9.5:

PCP 6.2.2
Grafana 10.2.6

Updated compiler toolsets

The following compiler toolsets have been updated in RHEL 9.5:

GCC Toolset 14 (new)
LLVM Toolset 18.1.8
Rust Toolset 1.79.0
Go Toolset 1.22

For detailed changes, see New features - Compilers and development tools.

The web console

With the new File browser provided by the cockpit-files package, you can manage files and directories in the RHEL web console.

See New features - The web console for more information.

RHEL in cloud environments

You can now use the OpenTelemetry framework to collect telemetry data, such as logs, metrics, and traces, from RHEL cloud instances, and to send the data to external analytics services, such as AWS CloudWatch.

See New features - RHEL in cloud environments for more information.

1.2. In-place upgrade

In-place upgrade from RHEL 8 to RHEL 9

The supported in-place upgrade paths currently are:

From RHEL 8.10 to RHEL 9.5 on the following architectures:
- 64-bit Intel and AMD
- IBM POWER 9 (little endian) and later
- IBM Z architectures, excluding z13
From RHEL 8.8 to RHEL 9.2, and RHEL 8.10 to RHEL 9.4 on the following architectures:
- 64-bit Intel, AMD, and ARM
- IBM POWER 9 (little endian) and later
- IBM Z architectures, excluding z13
From RHEL 8.6 to RHEL 9.0 and RHEL 8.8 to RHEL 9.2 on systems with SAP HANA

For more information, see Supported in-place upgrade paths for Red Hat Enterprise Linux.

For instructions on performing an in-place upgrade, see Upgrading from RHEL 8 to RHEL 9.

If you are upgrading to RHEL 9.2 with SAP HANA, ensure that the system is certified for SAP before the upgrade. For instructions on performing an in-place upgrade on systems with SAP environments, see How to in-place upgrade SAP environments from RHEL 8 to RHEL 9.

Notable enhancements include:

Properly close file descriptors for executed shell commands to prevent the common Too many opened files error.
Introduce in-place upgrade for systems with the Satellite server version 6.16.
Target the GA channel repositories by default unless a different channel is specified by using the --target leapp option.
Update the default kernel command line during the upgrade process so that kernels installed later automatically contain expected parameters.

In-place upgrade from RHEL 7 to RHEL 9

It is not possible to perform an in-place upgrade directly from RHEL 7 to RHEL 9. However, you can perform an in-place upgrade from RHEL 7 to RHEL 8 and then perform a second in-place upgrade to RHEL 9. For more information, see Upgrading from RHEL 7 to RHEL 8.

1.3. Red Hat Customer Portal Labs

Red Hat Customer Portal Labs is a set of tools in a section of the Customer Portal available at https://access.redhat.com/labs/. The applications in Red Hat Customer Portal Labs can help you improve performance, quickly troubleshoot issues, identify security problems, and quickly deploy and configure complex applications. Some of the most popular applications are:

1.4. Additional resources

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.

Major differences between RHEL 8 and RHEL 9, including removed functionality, are documented in Considerations in adopting RHEL 9.

Instructions on how to perform an in-place upgrade from RHEL 8 to RHEL 9 are provided by the document Upgrading from RHEL 8 to RHEL 9.

The Red Hat Insights service, which enables you to proactively identify, examine, and resolve known technical issues, is available with all RHEL subscriptions. For instructions on how to install the Red Hat Insights client and register your system to the service, see the Red Hat Insights Get Started page.

Note

Public release notes include links to access the original tracking tickets, but private release notes are not viewable so do not include links.^[1]

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