OK - Yes, I'm YEARS behind the vast majority here but TBH, I only rarely use my version of Poser 5 for the occasional piece of art. I have V3 and Aiko 3 installed, but there are a few characters for V4/A4 available.

My question - if I install them, will they work with my V3/A3 base figures?

V4 poses work fine with my older figures - even figures that aren't even Victoria. Here's hoping.