There are two ways to update to the latest version of DropDMG:
Automatic Updating
Manual Updating
Go to the DropDMG Web site and click the Download (Free Trial) button.
Quit DropDMG.
Replace the old DropDMG application file with the new one. That is, if DropDMG is installed in the Applications folder, drag the new DropDMG application icon into the Applications folder and click Replace when the Finder asks if you want to overwrite the old version. (If macOS won’t launch the app because it says that it’s damaged, please see the Download Fixer page.)
Note: If you get an error saying that the file is locked or you do not have sufficient privileges, drag the old DropDMG to the trash and empty it, and then drag the new one into the Applications folder.
Launch DropDMG.
Mac App Store
If you purchased via the Mac App Store, you should update DropDMG using the App Store application.
Upgrades
DropDMG 3.6.8 is a paid upgrade for registered users of DropDMG 1.x and 2.x. Discounts and free updates are available depending on when you originally purchased DropDMG.