How to downgrade Jenkins?

To downgrade Jenkins, follow these steps:

Step 1: Backup Your Data

Before downgrading, it's crucial to back up your Jenkins data to avoid losing any configurations or job data.

1. Backup Jenkins Home Directory:
   • Locate your Jenkins home directory (usually /var/lib/jenkins on Linux).
   • Copy the entire directory to a safe location.

Step 2: Stop Jenkins

Stop the Jenkins service to ensure that no processes are running during the downgrade.

• On Linux:

  sudo systemctl stop jenkins

• On Windows:

  • Use the Services management console to stop the Jenkins service.

Step 3: Download the Desired Version

1. Go to the Jenkins download page.
2. Find the version you want to downgrade to and download the appropriate package (WAR file or installer).

Step 4: Replace the Current Jenkins Installation

1. For WAR File:

   • Replace the existing jenkins.war file with the downloaded version.
   • The WAR file is usually located in /usr/share/jenkins or similar directories.

   sudo mv /path/to/downloaded/jenkins.war /usr/share/jenkins/jenkins.war

2. For Installer:

   • If you are using an installer, run the installer for the version you downloaded and follow the prompts to install it.

Step 5: Start Jenkins

After replacing the WAR file or completing the installation, start the Jenkins service again.

• On Linux:

  sudo systemctl start jenkins

• On Windows:

  • Use the Services management console to start the Jenkins service.

Step 6: Verify the Downgrade

1. Open your web browser and navigate to your Jenkins instance (usually http://localhost:8080).
2. Check the version displayed on the dashboard to confirm that the downgrade was successful.

Step 7: Restore Plugins (if necessary)

If you encounter issues with plugins after downgrading, you may need to reinstall or revert to compatible versions of those plugins.

If you have any specific questions or need further assistance, feel free to ask!