Thanks for the comments.  Just to clarify:

"Riptide" = free (I sometimes refer to this as "Riptide Classic" now).

"Riptide Pro" = the commercial one, that requires a purchase (but has a 30-day free trial period).

....for Riptide, there are older versions that can work with Cinema 4D starting back with R7.3 and the most recent one works with R9.1 or later.

For Riptide Pro, support starts with C4D R9.6 or later, but there is also a build for R10.1 or later which adds support for C4D "Layers" (which was added in R10.1). 

Cinema4D Plugins (Home of Riptide, Riptide Pro, Undertow, Morph Mill, KyamaSlide and I/Ogre plugins) Poser products Freelance Modelling, Poser Rigging, UV-mapping work for hire.