upgrading from 6.3 to 7.0 in my UAT instance.

[John Pfotzer]

What is the most successful way to do this?

[Naman Verma]

Step 1: Add-ons Compatibility
* Check the installed plugins for compatibility with the new version https://confluence.atlassian.com/upm/checking-add-on-compatibility-with-application-updates-273875705.html
* Move the incompatible plugin to a backup folder to avoid JIRA Startup issues after the upgrade.
* Doing so you can also always refer back to the backup folder to know what all Add-ons were installed.

Step 2: Upgrade from the current version to JIRA 7.0.0 ( along with the ServiceDesk 3.0.0 OR Software 7.0.0 ) https://confluence.atlassian.com/adminjira/jira-platform-releases/jira-applications-compatibility-matrix
* Download the JIRA installer from Atlassian website [Download|https://www.atlassian.com/download].

* Here please choose the correct Application (Jira Core, Jira Software, Jira Service Desk etc )
* Here you can click *“All Server versions”* link in blue just below the Download button to choose different versions.
* After Downloading the installer follow the steps in the link https://confluence.atlassian.com/adminjiraserver071/upgrading-jira-applications-using-a-rapid-upgrade-method-802592264.html
* Repeat the steps mentioned in Step 2 again to upgrade JIRA from 7.0.0 to the *Desired Version*.
* After Jira is up and running on your desired version reinstall plugin compatible with the newer version https://confluence.atlassian.com/upm/installing-add-ons-273875715.html

Note
* Please try any of the above steps on a test JIRA instance before doing any changes to JIRA production.
* Also please always take backups of JIRA DB and JIRA home directory before proceeding with any changes.