Gérald:

Two ways to get new versions of Poser for testing:

1: Poser 12 license is now available via Humblebundle at $25.-:

https://www.humblebundle.com/software/poser-12-3d-character-design-pack-software

Bondware confirmed this is fully ligit resale. I assume it also would make you eligible for upgrade to Poser13.

2: Poser13 has a free 21 days trial period. https://www.posersoftware.com/downloads

For Python 2 to 3 conversions: I usually start with a manual pass over the 'print' statements to put brackets around the arguments and from there work on error message feedback. 

You may also want to check this thread: https://www.renderosity.com/forums/threads/2954377/py2-to-py3-conversions