according to the manual Mac versions required is Mac OS X 10.15 or higher (64-bit OS required)

You can find the manual at the Poser website Menu > Support > Poser 12 Manual http://www.posersoftware.com/documentation/12/index.htm

direct link to the System Requirements: http://www.posersoftware.com/documentation/12/index.htm#t=Poser_Reference_Manual%2FIntroduction%2FWelcome%2FSystem_Requirements.htm

hope this information is helpful for you