How to use new apple OS with old devices?
Guide: How to Get Continuity on older Macs
Apple does not support Mac computers older than 2012.
Continuity Activation Tool should be used with caution as it moves around the part files in your system, so it is your responsibility that you use it, writes the developers.
With the new Continuity Activation Tool, you get an older MacBook Air from 2008 or a MacBook Pro from 2010 to work compliant to new Apple softwares with Continuity. Remember though that system requirements are still important for both OS X and iOS Yosemite 8th.
You can see the full list via GitHub.