Here are some important notes on upgrading to Confluence 9.4. For details of the new features and improvements in this release, see the Confluence 9.4 release notes.

Upgrade notes

Secure app installations with app signing

To improve app security, we’re introducing a new feature that will restrict app installations to only those that are signed. This will help us to:

• ensure that apps are either from Atlassian Marketplace or manually uploaded by trusted partners
• prevent malicious actors from uploading harmful apps

App signing affects only new app installations, already installed apps will remain intact.

This feature will be gradually rolled out across Data Center products by mid-2025. For details, check out this community post.

In this release, app signing is disabled by default. The grace period will last until the next feature release of Universal Plugin Manager (UPM), after which app signing will be enabled by default.

Use the grace period to adapt your processes. The steps you need to take differ depending on whether you install applications from the Marketplace or build your custom applications.

Enable app signing and install from Marketplace

During the grace period, you can enable app signing at your convenience. To do so:

1. Enable app signing. For details, see Configuring UPM app signature check.
2. Download and install Certificate Authority (CA) from Atlassian. For details, see Updating Atlassian Certificate Bundles.
3. That’s it! Enjoy the safe app installations from Marketplace.

Install custom apps

If you use custom application builds, you can sign and secure your apps:

1. Enable app signing. For details, see Configuring UPM app signature check.
2. Get the app signature and verification certificate as described in Generating app signature and verification certificate using OpenSSL.
3. Put your new certificate in your Trust store as described in Updating Atlassian Certificate Bundles.
4. Install the signed application.

If you’re experiencing issues, check out App signing troubleshooting.

Configure OAuth 2.0 for outgoing mail

To enhance security and align with Microsoft's deprecation of Basic authentication in Exchange Online, Confluence now supports OAuth 2.0 for outgoing mail (SMTP). This update allows administrators to authenticate using the OAuth 2.0 profile directly from the system admin UI. For detailed steps, check Configuring a server for outgoing mail.

App tunnels now bundled

The Application tunnels app is now bundled with Confluence Data Center. There is no need to install it separately from the Atlassian Marketplace; you will find it pre-installed under Administration > Application Tunnel.

Supported platforms changes

There are no platform changes in this version. See the complete list of supported platforms

End of support announcements

There are no advance announcements this time.

For more information on these notices, see End of Support Announcements for Confluence.

Infrastructure changes 

Head to Preparing for Confluence 9.4 to find out more about changes under the hood. 

Known issues

Issue with network interfaces resolution after the upgrade to 9.1.x and later

The network interface naming algorithm has changed in JDK/JRE21 for Windows OS. As a result, after upgrading to Confluence 9.1.0 or a later version on Windows instances, Confluence or Confluence-managed Synchrony may not start. 

For instructions on how to fix the issue, refer to this KB article: Confluence Data Center won't start due to no matching network interface found. To track the progress of issue resolution, see CONFSERVER-99116.

Other known issues

• There are a number of known issues when upgrading Confluence on specific database versions. See Confluence 7.11 upgrade notes if you are upgrading from Confluence 7.10 or earlier.
• If you are upgrading from Confluence 6.3 or earlier, there's a known issue where spaces do not appear in the space directory. You'll need to reindex your site after upgrading to fix this. 
• If you use Apache to limit who can access the admin console, you should update your configuration. See Using Apache to limit access to the Confluence administration interface for our suggested configuration.
• There is a known issue where read-only mode attempts to write to <shared-home>/confluence.cfg.xml , but the file doesn't exist in the shared home directory. This problem affects sites that have been previously upgraded from Confluence 6.0 or earlier. See Could not save access.mode into the shared confluence.cfg.xml file error after upgrading to Confluence Data Center 6.10
• There is a known issue where some fonts that Confluence relies on are not available in older Linux distributions. See Confluence UI shows garbled or corrupt text on CAPTCHA, macros, and/or diagrams due to missing fonts
• There is a known issue where Confluence 8.8.0 and 8.8.1, upon upgrade from earlier versions, will fail to render the login page for instances using custom layout decorators. The decorators could be using the resource './langmacro.vm' that is no longer included in Confluence 8.8 (and later). See After Upgrade , error encountered - ResourceNotFoundException: Unable to find resource '/langmacro.vm' for more information.

If you encounter a problem during the upgrade and can't solve it, please create a support ticket and one of our support engineers will help you.

Upgrade procedure

Always test the upgrade in a test environment before upgrading in production.

To upgrade Confluence to the latest version:

1. From the Administration menu , select Manage apps, and then Confluence update check to verify the compatibility of your user-installed apps with the target application version.

2. From the Administration menu , select General Configuration, and then Plan your upgrade and the version you want to upgrade to. This will run the pre-upgrade checks.
3.  From the Administration menu , select General Configuration, and then Troubleshooting and support tools to check your license validity, application server, database setup, and more.
4. If your version of Confluence is more than one version behind, read the release notes and upgrade guides  for all releases between your version and the latest version.
5. Back up your installation directory, home directory, and database.
6. Download the latest version of Confluence.
7. Follow the instructions in the Upgrade Guide.

Update configuration files after upgrading

The contents of configuration files such as server.xml, web.xml , setenv.bat / setenv.sh, and confluence-init.properties change from time to time. 

When upgrading, we recommend manually reapplying any additions to these files (such as proxy configuration, datasource, JVM parameters) rather than simply overwriting the file with the file from your previous installation; otherwise you will miss out on any improvements we have made.