Here are some important notes on upgrading to Confluence 6.6. For details of the new features and improvements in this release, see the Confluence 6.6 Release Notes.

Confluence 6.6 is a Long Term Support release
This means we'll provide bug fix releases until 6.6 reaches end of life, to address critical security, stability, data integrity, and performance issues. 
Ready to upgrade? Check out the Confluence 6.6 Long Term Support release Change Log for a roll-up of changes since 6.0. 

Upgrade notes

• Upgrade notes
  • SQL Server driver update
  • Performance improvements
  • Update configuration files after upgrading
  • Upgrading from Confluence 5.x?
• Infrastructure changes 
  • For developers
  • End of support announcements
• Known issues
• Upgrade procedure
• Checking for known issues and troubleshooting the Confluence upgrade

Changes to the Share a link blueprint

From Confluence 6.6.13 URLs must be added to Confluence's whitelist before they can be shared using the Share a link blueprint. This is to prevent people from accidentally or maliciously sharing links that may pose a security risk to your site.  

SQL Server driver update

We have now replaced the open source jTDS driver for Microsoft SQL Server with the official Microsoft JDBC Driver for SQL Server. 

If you're still using the jTDS driver to connect to Microsoft SQL Server, we'll switch you to the new driver automatically, after you upgrade to Confluence 6.6.

If for some reason this fails (for example, if you're using a datasource connection), you'll need to make this change manually. See this knowledge base article to find out how to switch.   

If you're using Data Center, you'll need to make sure Synchrony is also using the new driver. More information in this knowledge base article. 

Performance improvements

We've made some changes to reduce the CPU and memory load of actions that search for users, for example mentioning someone, sharing a page, and selecting a user in a blueprint field or macro parameter. 

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) 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

Head to Preparing for Confluence 6.6 to find out more about changes under the hood.

End of support announcements

As previously announced:

• The jTDS driver for Microsoft SQL Server is no longer supported. 
• The JUnit Report macro is no longer supported. This macro will be removed in a future release.  

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 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.