With the recent works on identifying and fixing two main issues affecting customer upgrades to Jira9, we should review and update our upgrade guides and reference materials.

Jira 9 upgrade relevant issues

• JRASERVER-74787 — Full reindex operation slow down in Jira 9.0.0
• JRASERVER-74882 — Restarting Jira 9 after upgrading from Jira 8 triggers a full reindex regardless of Reindex configs

Current upgrade-related articles

• Jira 9.4 Long Term Support release upgrade guide (main upgrade guide)
• Preparing Jira for the 9.4 upgrade
• Upgrading Jira Data Center to 9.4
• Upgrading Jira Server to 9.4
• Upgrading Jira (installer) (general installation guide)
• Upgrading Jira (manual) (general installation guide)

KB article as reference

This KB article was published in the meantime to address the more practical aspects of the Jira 9 upgrade procedure and focus on the issues impacting customers the most:

• Practical guide on upgrading Jira Data Center to version 9 or 9.4 LTS

Once it's contents are incorporated into the existing guides, we can deprecate this KB with a warning macro, list the updates articles there and eventually archive it.