Support will be dropped for Windows 8.1, Windows 10 v1511 and v1607, and Mac OS 10.11 (El Capitan):
If you’re running Windows 8.1, Windows 10 v1511 and v1607 or Mac OS 10.11 (El Capitan), you can continue to run and install current and previous versions of Creative Cloud applications. However, you will not be able to install or run the next major release of Creative Cloud unless you’re on a supported version of Windows or MacOS.Users of older versions of Windows and macOS will be able to continue to use their existing Creative Cloud apps, but will not receive updates.
Creative Cloud Desktop, which manages application installs, will continue to be supported on Windows 7 or later and Mac OS X v10.9 or later.