Here are some important notes on upgrading to Confluence 6.3. For details of the new features and improvements in this release, see the Confluence 6.3 Release Notes.

Upgrade notes

Maximum editors limit

To prevent potential performance issues, the maximum number of people who can edit a page simultaneously is now limited to 12. This means that people can't enter the editor if there are already 12 other people editing the page, and will need to wait until someone leaves. You can increase or decrease this limit using the confluence.collab.edit.user.limit system property.

Updated database drivers

• If you use MySQL, you can now use the latest driver (5.1.42).  
• If you use Oracle, you'll need to use the latest driver (12.2.0.1) to upgrade to Confluence 6.1 or later. 
• We've upgraded the bundled PostgreSQL driver to the latest version (42.1.1). 

Update configuration files after upgrading

The contents of configuration files, such as server.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 etc) rather than simply overwriting the file with the file from your previous installation, otherwise you will miss out on any improvements we have made.

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:

• Memory and CPU: You may need to give your server more resources than for previous Confluence releases. When you install Confluence, Synchrony (which is required for collaborative editing), will be configured to run as a separate process on your server. The default maximum heap size for Synchrony is 1 GB (on top of Confluence's requirements). 
• WebSockets: Collaborative editing works best with WebSockets. Your firewall / proxy should allow WebSocket connections. 
• SSL termination: SSL should be terminated at your load balancer, proxy server, or gateway as Synchrony does not support direct HTTPS connections. 
• Database drivers: You must use a supported database driver. Collaborative editing will fail with an error if you're using an unsupported or custom JDBC driver (or driverClassName in the case of a JNDI datasource connection). See Database JDBC Drivers for the list of drivers we support.
• Database connection pool: your database must allow enough connections to support both Confluence and Synchrony (which defaults to a maximum pool size of 15). 

Infrastructure changes 

For developers

There were a few library upgrades in this release which may have an impact on add-ons. 

Head to Preparing for Confluence 6.3 to find out more about the changes.

New supported platforms

In this release we've added support for:

• PostgreSQL 9.6
• MySQL 5.7

End of support announcements

• End of support for Oracle Solaris
  As previously announced, from this release onward we no longer support running Confluence on Oracle Solaris operating systems. 

See End of Support Announcements for Confluence for more information.

Known issues

• 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 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.
• Confluence Collaborative Editing does not work with SSL and Apache 2.4.9 or earlier.
• 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 Administration  > General Configuration > 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 6.2, 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.