From PocketWizard:
Mac OS X El Capitan Note
At this moment, our PocketWizard Utility appears to be incompatible with Mac OS X El Capitan. Something has changed in how they handle USB devices. We're looking into it. In the meantime, you'll either have to refrain from updating to El Capitan to work with the PocketWizard Utility, or find another machine to use it on. We're not the only ones experiencing issues:
Their new System Integrity Protection shifts how things work. It impacts some simple connectivity stuff we've relied upon. We are researching solutions now:
5DS Beta
The current Canon ControlTL beta firmware version is 6.804 and is available through the PocketWizard Utility right now. It adds support for Canon's latest DSLR, the Canon EOS 5DS. [Release Notes]
B&H carries PocketWizard products.