I’m running into an issue while trying to upgrade Jenkins from 2.361.1 to the latest version, 2.568.1. After stopping the Jenkins service and replacing the WAR file with the latest 2.568, the website no longer loads. Instead, it displays an error page with lines of code. We are aware that the latest Jenkins version requires JDK 25, and we have installed it, but we are still experiencing the same issue.
This upgrade was initiated because users were unable to authenticate via LDAP, and we noticed the LDAP plugin was outdated on version 2.12, so we decided to upgrade.
Could you provide any guidance on what might be causing this issue or what we should check next?
Going from 2.361.1 to 2.568.1 is a very big jump. 2.361.1 is around 4 years old.
Read the the upgrade guides for all versions up to the latest here: Jenkins LTS Upgrade Guide
Some plugins fail to load because they are too old. E.g. an old ldap plugin will fail to load on 2.479 or newer due to switch from EE8 to EE9.
Check the complete jenkins log for plugins that fail to load.
Take a backup of the complete JENKINS_HOME before doing anything in case you haven’t yet done that already.
Ideally set up a test Jenkins that is a copy of the old one (without the jobs), then try to upgrade that to the target version.
My recommendation is to use GitHub - jenkinsci/plugin-installation-manager-tool: Plugin Manager CLI tool for Jenkins · GitHub.
Take note of all plugins that you have installed. Then with the plugin manager tool download all required plugins for the new Jenkins version and put them in the plugins folder of the test instance and try to start it. Chances are good that it starts without issues
Is there a guide I can follow? This is my first time dealing with Jenkins, so I’m not familiar with the application. I’ve reviewed the links, but I still don’t understand.
