Proficy Machine Edition. It will need to be a recent enough version to include the Quick Panel Plus.
PME uses a common database for both PLC and HMI targets within the same project, so you will need a license for "View" if the Quick Panel Plus is just going to communicate with a PLC. If the PLC is a GE product and you want the PLC's program to be part of the same project as the QP+ you will need your Proficy Machine Edition installation to be licensed for Logic Developer PLC in addition to View.
The previous is from personal experience. Now I'm getting into speculation. If you plan to run the logic program on the QP+ you will probably need a license for Logic Developer PC instead of Logic Developer PLC.
When Russ sees this thread he will probably be able to tell you exactly which version you will need to be at and to confirm or correct what I said.