This update released on April 20, 2015 resolves a security vulnerability discovered in a large number of plugins through the collaborative efforts of the WordPress core development team, dozens of plugin developers, and researchers at Sucuri.com.
Each version “branch” of Easy Digital Downloads will be updated separately. This means that if are still running version 2.1, you will be updated to version 2.1.11. If you are running version 1.8, you will only be updated to 1.8.7. This has been done so as to minimize changes to your sites as much as possible.
All the details here