Here are some important notes on upgrading to Confluence 6.12. For details of the new features and improvements in this release, see the Confluence 6.12 Release Notes. 

Upgrade notes

Additional memory requirements for Data Center nodes

If you choose to allow Confluence to manage Synchrony for you, you'll need to allow an additional 2GB RAM for the Synchrony process, on every Confluence node. 

If you're upgrading from Confluence 6.9 or earlier, don't forget you'll also need to allow an additional 2GB for the external process pool, which handled document conversion and PDF exports. 

You can read more about the memory requirements in our Data Center Technical Overview. 

Changes to PDF export in Data Center

As mentioned in the release notes, PDF export is now handled by the external process pool in Data Center. You may find that spaces that previously exported slowly, but successfully, may fail now that we have implemented a timeout. Particularly if the spaces include pages with a large number of web images (that are not attached to a page). 

If you do experience timeouts, you can either increase the time limits using system properties, or choose not to handle PDF exports in external process pool. See  PDF export in Confluence Data Center for more details. 

Changes to editor icons

Icons in the editor got a smart new look in this release, and a few table icons have changed significantly. Here's a 'before and after' to help you out. 

We've also improved many of the icons in the Insert menu, including adding a new item for inserting a date lozenge. 

Add-ons are now known as Apps

We've renamed "add-ons" to "apps" throughout Confluence, to match the terminology used on the Atlassian Marketplace. 

To view and modify system and Marketplace apps go to  > Manage apps. 

Supported platforms changes

• Advance notice: end of support for PostgreSQL 9.3 
  Confluence 6.13.x will be the last release to support PostgreSQL 9.3. 

Update configuration files after upgrading

The contents of configuration files such as server.xml, web.xml , setenv.bat / setenv.sh and confluenceinit.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.

Check for Atlassian Companion MSI updates

The Atlassian Companion app manages the download and re-upload of files edited in Confluence. If you distribute the Companion app using the Microsoft Installer (MSI), the app won't automatically get the latest security updates and bug fixes. Check the Atlassian Companion app release notes to make sure you're running the latest version.

Upgrading from Confluence 5.x?

Collaborative editing is made possible by the magic of Synchrony. When you install Confluence Server, Synchrony will be configured to run as a separate process on your server.

If you're upgrading from Confluence 5.x, there are a few requirements you need to be aware of:

Infrastructure changes 

For developers

Head to Preparing for Confluence 6.12 to find out more about changes under the hood. 

End of support announcements

No announcements. 

Known issues

• Users can't edit files using the Atlassian Companion app in some browsers. See Can’t edit files in Confluence Server using Atlassian Companion app in Internet Explorer, Edge, Firefox, or Safari
  
• 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 the "hibernate dialect" property was being incorrectly retained after upgrade. Customers who have been using Confluence since version 2.4 or earlier (legends!) should check the hibernate dialect in their <confluence-home>/confluence.cfg.xml file before upgrading to Confluence 6.x to avoid this error: Upgrading fails with ERROR The size (16777215) given to the column 'event' exceeds the maximum allowed for any data type (8000) in Confluence.
• There is a known issue when upgrading Confluence with an Oracle database. Oracle users should upgrade their driver to 12.2.0.x before upgrading to Confluence 6.1 or later. See Upgrade to version 6.1.x Failed With Error "ORA-01000: maximum open cursors exceeded" for more information. 

Upgrade procedure

Note: Upgrade to a test environment first. Test your upgrades in your test environment before rolling them into production.

If you're already running a version of Confluence, please follow these instructions to upgrade to the latest version:

1. Go to > Support Tools > Health Check to check your license validity, application server, database setup and more.
2. Before you upgrade, we strongly recommend that you back up your installation directory, home directory and database.
3. If your version of Confluence is earlier than 6.5, read the release notes and upgrade guides for all releases between your version and the latest version.
4. Download the latest version of Confluence.
5. Follow the instructions in the Upgrade Guide.

Checking for known issues and troubleshooting the Confluence upgrade

After you have completed the steps required to upgrade your Confluence installation, check all the items on the Confluence post-upgrade checklist to ensure that everything works as expected. If something is not working correctly, please check for known Confluence issues and try troubleshooting your upgrade as described below:

• Check for known issues. Sometimes we find out about a problem with the latest version of Confluence after we have released the software. In such cases we publish information about the known issues in the Confluence Knowledge Base.
• Check for answers from the community. Other users may have encountered the same issue. You can check for answers from the community at Atlassian Community.
• Did you encounter a problem during the Confluence upgrade? Please refer to the guide to troubleshooting upgrades in the Confluence Knowledge Base.

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.