To check for a new version of Bookit online simply select "Check for Update" from the Help menu. This will open the Bookit homepage where the current version number is at the top of the page next to the name. If the current version number is greater than the version currently installed then the updated Bookit should be downloaded.

Tip: To check what version of Bookit is installed launch Bookit and select "About Bookit" from the Apple menu. The version is located after the name.