They definitely support SSD Cache. And eehm, they also kind of support SHR. I migrated my SHR2 array from a DS2415+ unit to this one after the old unit failed. That works just fine, because SHR is disabled by a software switch. That’s a really roundabout way to get SHR though. There is a much simpler one. Just edit the settings file.
But I doubt the 2 are related since SSD cache doesn’t rely on SHR.