As Nerd said you can have multiple version of Poser on the same system.  I currently have 25 copies of Poser 13 on the system and it is really easy to do.  

1: When you first install Poser place it outside of the programs folder.  That way you don't run into permission issues.  I have mine on E:Poser:Poser 13.

2: Prior to installing a new version I will (with Poser Closed) rename the Poser 13 folder to z(version#)Poser 13.

3: Install the new version.  It will find the old location and offer to install there. Install and you now have the latest version with access to the shortcuts and file associations.

4: If you need to run a prior version close the current one along with the Queue Manager (if running) find the proper prior version folder and inside that folder double click the Poser Program icon.

This way you can test to see if the program is working the same way between versions or if an issue has ben fixed.  Also it ensures that there are no leftover bits hanging around that may cause problems.

Poser 5, 6, 7, 8, Poser Pro 9 (2012), 10 (2014), 11, 12, 13