Upgrade from Smart Checklist Free to Pro is effortless, safe, and takes 1minute. All you need is to install the Pro version and remove the Free one. Your data will not be lost during the migration as both addons use the same storage Read How to Upgrade from Free to Pro Plan guide for more details
Smart Checklist for Jira. Сomparison of Free vs Pro Plan
for teams that use small checklists for short-term ad-hoc projects.