On 29th June 2017 Atlassian announced a new pricing structure for JIRA and Confluence Cloud as well as all Marketplace add-ons for Cloud, to make the pricing structure more flexible. Here's how it might affect you.
Switching draw.io for JIRA Server to being free on the 18.104.22.168 release seems to have causing a caching issue with users who previously had a license key applied to the add-on. We've released 22.214.171.124 to force a fix for this. Please upgrade, if you continue to have any problems, please email firstname.lastname@example.org. [...]