A single Dropshare for Mac license can, unless otherwise stated, be activated on up to 3 different Macs.
Starting with Dropshare 5.28 and newer, license activations can be reset in a self-service manner from within the app.
Open the menu, go to About and License Activations on a Mac that has a currently licensed version of Dropshare installed.
Otherweise, we will however reset your activation count if required. Just send us an informal message that explains shortly why you need more activations of your license.