Here are some important notes on upgrading to Confluence 7.4. For details of the new features and improvements in this release, see the Confluence 7.4 Release Notes. 

Upgrade notes

Confluence Server and Data Center 7.4 is a Long Term Support release
This means we'll provide bug fix releases until 7.4 reaches end of life, to address critical security, stability, data integrity, and performance issues. 

Ready to upgrade? Check out the Confluence 7.4 Long Term Support release Change Log for a roll-up of changes since 6.13. 

Upgrading to 7.4.17

Due to changes in Confluence 7.4.17, you won't be able to perform a rolling upgrade to this version. Downtime will be required. 

You must wait for node 1 to start completely after upgrading before you attempt to start the next node, or Confluence will fail to start with an 'Unexpected bytes from remote node' error. If this happens, restart your first node. 

It is always good practice to wait for a node to start up completely before starting the next node. 

Word and Excel conversion now handled by the external process pool

In Confluence Data Center, many memory and CPU intensive tasks are handled by the external process pool. 

From Confluence 7.4.7, the HTML conversion that's required to display a Word or Excel file using the Office Word and Office Excel macros (provided by the Office Connector) will be handled by the external process pool. 

PostgreSQL driver upgrade

In 7.4.6 we upgraded the PostgreSQL driver bundled with Confluence from 42.2.6 to 42.2.16.

In 7.4.8 we upgraded the PostgreSQL driver bundled with Confluence from 42.2.16 to 42.2.18.

We don't expect there to be any impact from these driver upgrades. See the PostgreSQL JDBC driver changelog if you want more details.  

Size limit for drop shadow image effect

Applying a drop shadow image effect to images with a high pixel density can cause out of memory errors. From Confluence 7.4.4, we now prevent users from applying a drop shadow to images larger than 2000x2000 pixels.  System administrators can change this limit using the atlassian.image_filter.transform.max.pixel.drop_shadow  system property.

Custom plugins and integrations

If you're upgrading from Confluence 6.x and you've built your own plugins and integrations, be aware that Confluence 7.0 contained significant changes that might affect your plugins. 

We recommend you review the following developer resources, and test your custom plugins thoroughly before upgrading to Confluence 7.4 in production. 

• Preparing for Confluence 7.0
• Confluence 7.0 developer guide
• Atlassian User Interface upgrade guide
• Deprecated code paths removed in 7.0

Inspect permissions with external directories

We've improved how the People who can view and Inspect Permissions features work with complex external directory scenarios. The following scenarios are now supported:

• Nested groups 
• Non-aggregating group membership
• Disabled directories
• Disabled user accounts in one, but not all, directories
• Groups names that contain upper-case characters

Note: when you inspect permissions for a specific group, we only report the permissions granted directly to that group. We'll warn you if the group is nested, but won't show permissions granted to any parent groups (you'll have to inspect these separately). This limitation only applies when you inspect permissions for a group. When you inspect permissions for a user, we display permissions granted by all groups, including parent groups.

Upgrading from 6.x

If you set up your mail server using a JNDI location (in the server.xml ), there are now two additional jar files that you'll need to move from <confluence-install>\confluence\WEB-INF\lib to <confluence-install>\lib : 

• javax.activation-x.x.x.jar
• javax.activation-api-1.2.0.jar

Upgrading from 6.3 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. 

Supported platforms changes

As previously announced, the following databases are no longer supported:

• PostgreSQL 9.4
• MySQL 5.6 
• Oracle 12c R1
• Microsoft SQL Server 2012

Reminder about operating system support

Microsoft ended support for Windows 7 on January 14. You should only install and use Confluence on operating system versions that have active vendor support.

End of support announcements

Advance Notice: End of support for Internet Explorer 11

To allow us to continue to take advantage of modern web standards to deliver improved functionality and the best possible user experience across all of our products, we have decided to end support for Internet Explorer 11. 

Confluence 7.4.x (Long Term Support release) will be the last release to support Internet Explorer 11. 

Advance Notice: End of support for several databases 

Confluence 7.4.x (Long Term Support release) will be the last release to support the following databases:

• Microsoft SQL Server 2014
• PostgreSQL 9.5

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

Infrastructure changes 

Head to Preparing for Confluence 7.3 to find out more about changes under the hood. 

Known issues

• There is a known issue when running Confluence with MySQL 8.0.29 and later due to a change to the UTF8 alias in MySQL. We're working on a fix, but if you have Confluence 7.3 or later, you can change the character set and collation to UTF8MB4 to avoid this issue. See How to Fix the Collation and Character Set of a MySQL Database manually.
• There's a known issue in JavaMail 1.6.2 which may affect you if you set up your mail server in the server.xml. See CONFSERVER-59040.
• Synchrony will not start on Windows with AdoptOpenJDK jdk8u212.  See CONFSERVER-58784) for a workaround.
• 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. 

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. Go to Administration  > General Configuration > Plan your upgrade and select the version you want to upgrade to. This will run the pre-upgrade checks.
2. Go to Administration  > General Configuration > Troubleshooting and support tools to check your license validity, application server, database setup and more.
3. 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.
4. Back up your installation directory, home directory and database.
5. Download the latest version of Confluence.
6. 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.