To manually upgrade your Jira instance, perform the following steps:

1. Take your current Jira offline.
2. Install the new version of Jira in a different directory.
3. Edit the jira-application.properties file in the JIRA_INSTALL/atlassian-jira/WEB-INF/classes directory to point to the existing JIRA_HOME directory.
4. Copy any modified files from the old Jira instance to the new one.
5. Start up the new Jira instance.
6. Update the add-ons once Jira starts successfully.
7. Remove the previous installation directory to avoid confusion.