This update greatly improves performance and stability, and is recommended for all Checkout users.
Your store database will be updated for this version of Checkout and will not be usable with older versions afterwards. Your data will not be harmed, but it is always wise to have a backup.

This update fixes the conversion issues in the previous 2.1 update. If you downloaded 2.1 before, please install this update, then reboot your Mac and start Checkout again.