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Quote - and if the installed dynamic cloth function actually works since there's no request for a serial number.

  By default (at least in DAZ Studio Pro) it appears you get the basic version of the Dynamic Clothing Control built in.  If you own the full plugin version http://www.daz3d.com/shop/dynamic-clothing-control , I assume you would probably need to reset your downloads and install any updated version and could enter a serial number at that point.   

The product page says it has been updated for DAZ Studio 4.5, although it apparently depends on your OS:  I see conflicting notes, one says "Note: This has been updated to work with DAZ Studio 4 and DAZ Studio 4.5 (32 and 64 bit Mac and Windows.) (There are still known issues with Mac OS 10.7)." and the other, presumably old incorrect note says "Dynamic Clothing is only supported on the PC in the 32-bit version of DAZ Studio 3."