Cinema 4D version
X-Particles 4 will work in any of these Cinema 4D versions:
A 64-bit machine is required. There are no lower memory limits, but larger amounts of memory will allow larger numbers of particles to be generated.
Either a 64-bit version of Windows 7 or later, or OSX 10.8.5 (Mountain Lion) or later. Note that Cinema 4D itself may have different requirements, especially depending on the version of OSX you are using. The latest requirements for Cinema 4D can be found on the MAXON website.
X-Particles must validate your licence after installation and once within every 21 days after that. Therefore to use it your machine MUST have access to the internet before you use it for the first time and sufficiently often after that to enable repeat validation. It does not require constant net access all the time.
Needless to say, internet access is required for the online updater to work, but you don't have to use the updater if you don't want to.
Other Cinema 4D modules
For use with C4D’s Dynamics, a version of Cinema 4D containing the Dynamics system is required.
Thinking Particles and/or Hair
Thinking Particles is NOT required to use X-Particles. The only advantage of having Thinking Particles is that you can use the X-Particles emitter to generate Thinking Particles, which you could then render with Pyrocluster or the Hair renderer.
However, the X-Particles material provides a better solution to render particles instead of Hair, and its volumetric rendering is superior to Pyrocluster. Therefore if you don't have these modules, there is no loss of functionality within X-Particles.