I am currently at Poser 11. I have original content and models dating back to Poser 9 and before. I watched the forums when poser 12 came out and it had enough changes that people seem to have a lot of problems with it.

What sort of backwards compatibility does poser 13 have? Are all of my old content models and attributes going to be scrap?

What functions are no longer going to work from P11, like scripts, etc.?

Am I going to run into a bunch of issues opening older scenes/models (V4 and M4) ?

Are the new features and dash worth the price and potential time suck to convert over?

Tom,

You can download the latest Poser 13 and take advantage of our free trial offer to see if it works for you.  The free trial does not have all the Included Content (new figures) until you purchase a license and activate it.  But you can add your existing Poser 11 Runtimes and things should mostly just work.

-Tim

Everything related to the runtimes will be handled correctly by Poser 13.
The problem comes with the Python scripts: Poser 11 is linked to Python 2.7,  Poser12+ are using Python3.x, which means that they won't work, especially the compiled versions (*.pyc & *.pyo)
BUT...
Nothing forces you to uninstall Poser11: all runtimes may be shared.
For example, I have a  hard drive (an SSD in fact) dedicated to Poser:

So: your old scripts can be run using Poser11, the result stored to a specific runtime shared by all Poser versions and voila.
In my case, I have a big collection of Vic4 (many ported to Sasha-19).

Poser 13 differs from Poser 12 in many aspect: performance for the Superfly engine (especially the OptiX version if your card support it), many bugs in the Cycles part corrected and enhanced, Cycles-X implemented in Poser 13 (that version is by itself faster, too, and more conform to the one of Blender), Physical node really enhanced too..

For your old scenes: the most secure is to copy them in a new hierarchy. Example:

Old figures should work in Poser 13. I've used the Mil 3 and 4 figures in Poser 13 with no issues. As Phil said, Python scripts will probably be an issue. There's a thread in the Poser python forum that can help make some of them usable. I was able to follow it and I don't know Python from basic.

If you want to use the Superfly render engine, the shaders will probably need to be updated. While Poser tries to render them, most of the time, they don't turn out like you'd want.

Like Tim suggested, to see if it works for you, try the trial. You can have multiple versions of Poser on your machine so the trial won't cause issues with your current version.

yea, i keep multipled version of Poser installed usually too. They're all sharing the same runtimes just fine.  Just need to keep old versions in order to use older python scripts like D3D stuff.  so its nice for certain situations and then I can open them in P12 or P13 to take advantage of newer features.

Poser 11 can co-exist with later versions.You may want to keep it, as E-on Vue (now free) needs it to import Poser scenes. Also, it will run older scripts.

Older figures will load fine in P12/P13, it's the scripts you will have problems with. Poser moved up to Python 3, and many broken Python 2 scripts needed either updating or replacement. Several years after all the fuss, most things are fixed in that regard. See... https://jurn.link/dazposer/index.php/p12/ 

Thanks you all for the input!