I have a backup from a Mavericks 10.9 computer which is bootable. I bought a newer Macbook Pro 2015 (models prior to touchbar). I tried to boot from the external backup but all I got was a grey screen with a stop sign in it and then the computer shutdown. I am assuming the newer mac models don't support or run on Mavericks. So which model can I buy that will run Mavericks backups?