The disk image is "internet-enabled", meaning that it will automatically dismount and trash itself after decompression. Both downloads contain the same, latest version of Bookdog, and a link to installation instructions for those who are new to the Mac's simple drag-and-drop installation. Let us know if you have trouble downloading.
Upgrading. If you have Bookdog 4.2.11 or later, launch Bookdog and click menu ► Bookdog ► Check For Updates. For earlier versions, download one of the above and then read the file For Upgraders. Pricing: Bookdog upgrades are free for all licensed users.