Lots of bug fixes in JIRA 6.2.4 which you can read in the JIRA 6.2.4 Release Notes.

Upgrading to JIRA 6.2.4 is free to all customers with active JIRA software maintenance and if you using our JIRA OnDemand service you'll automatically have all these fixes real soon.

Take a look at all the new features in the main JIRA 6.2 Release Notes and see what you are missing out on. Visualize development!