Here are the latest system requirements for the Photokey application.
Windows 7, Windows 8, Windows 10, OS X 10.9 Mavericks, OS X 10.10 Yosemite or OS X 10.11 El Capitan
64-bit operating system
550MB free hard disk space for installation
Internet connection is required for activation and web services
Intel Core i3, Core i5, Core i7 or AMD equivalent
2GB RAM (4GB or more recommended)
Photoshop plug-in: Requires Adobe Photoshop CC2015 (64-bit only)
As you can see, it supports Windows 7 and newer versions of Windows as well as Mac OSX.
You ca download a trial through the following page: https://fxhome.com/photokey/download