upgrade jira from 8.2 to 9.3 version

[nana Grace]

How do I upgrade jira from 8.2 to the new 9.3 version

[Nic Brough -Adaptavist-]

Welcome to the Atlassian Community!

First hit on every search engine - https://confluence.atlassian.com/adminjiraserver/upgrading-jira-applications-938846936.html

[nana Grace]

Thank you. I have gone through this doc earlier. could you please clarify the difference between Jira Server or Data Center (non-clustered) and Clustered Jira Data Center. 

thanks

[Nic Brough -Adaptavist-]

Jira Server is going away in a few months but is similar to a single-node DC installation. 

There are some system things you would configure a bit differently on a server and a single node DC, but both the server and the node are a single installation of Jira running on one machine, providing one Jira service.

A clustered DC simply has more than one node - it's a series of installations, running in more than one place, providing one Jira service.