Which license do I choose when purchasing an app/add-on/plugin?

Purchase the license tier that matches the number of users you have licensed for your host product. For example, if you have a 25-user Confluence license, purchase the Confluence app at the 25-user tier. The app will only function if its license matches or exceeds the tier of the host product – even if only some of your licensed users need to use the app.

For Jira, you must purchase the app license that matches the highest Jira application tier. For example, if you have a 500-User Jira Software license, and a 20-Agent Jira Service Desk license, your Jira apps must be at the 500-User level. 

If you own a legacy Jira Unlimited (100+ users) or Confluence Unlimited (2000+ users) license purchased in 2012 or earlier, legacy app pricing is no longer available.