MacRumors Forums:

Created by Dokterdok (based on instructions compiled by UncleSchnitty) and available on Github, the Continuity Activation Tool is designed to activate Continuity by doing a compatibility check, creating backups of original System drivers, and disabling a Mac-model blacklist in the Bluetooth code that prevents Continuity from working on ineligible Macs. From there, it also whitelists Mac board-ids within the Wi-Fi code to get the feature working.

The tool can be downloaded as a zip file from Github and is installed by double clicking the app and following the instructions provided on the screen.

The Continuity Activation Tool will enable Continuity on the mid-2011 MacBook Air and the mid-2011 Mac mini with no additional hardware required, as both of those devices include Bluetooth 4.0. That means installing the tool should get Continuity up and running on those machines in just a few minutes.

I’m not sure I’m willing to take the risk, but we’ll see. I really want to be able to use AirDrop on my 2011 MacBook Air.