Loveoption9

HI All, I'm a new user of Cura, and I have it running beautifully on one mac and was really wanting to run it on my older platform running OS 10.11.6. I installed 4.12 and got the circle with the line on the app icon. Reading further I thought that v 4.10 would work, but I keep getting the circle with the line telling me that I need 10.11.13 for even 4.9? I am suspecting that there is some plist snag that is causing the mac to keep seeing the newer app. Any suggestions on how to resolve this. My other option is Windows XP, is there an app that will run that old os? Thanks Tom