figures rigged with P7 type tools/conventions will work in DS4 ( as in DS3 etc)

figures rigged like Miki3 do not work in DS ( but can have the rigging tweaked to do so)

anything that uses PMD will work up to DS3 ( with a script from the Freepozitory)

.pp2, ,cr2, ,hr2  etc work fine in all versions of DS.

Poser procedurals/shaders do not work in DS, ordinary materials/textures do ( need adjustment in Surfaces usually)

lights and cameras do work in DS, but not in a predictable way ( and any lights with images attached will not show the image, native DS default lights have no channel to plug an image file into)

dzShader lights CAN have a channel for an image, and of course the 'uberlights' do have a channel to plug  images into.

magnets do work in DS ( they get converted to D-Form, but may not do exactly the same as in Poser)

 

 nearly forgot, MT5 and MC6 files do not work in DS ( but can sometimes be converted to .pz2, then they work, but without any of the procedural/shaders, just the basic texture, if applicable)

 

hope this helps