Unfortunately, I have not seen such a matrix. The approach to take is for each device:
1) Look up the minimum required firmware in the product datasheet. This brings you for the AP-204 ArubaOS 6.4.1.0 or InstantOS 4.1.1.0, and for the Aruba 650 the datasheet is no longer available but as it predates the AP-204 the minimum version for the 650 will not be the issue.
2) Look up the last supported version per product on the Aruba End-of-life page. There you can find that the 650 controllers can run up to ArubaOS 6.4.x, and the AP204 has not yet the last version defined for controller-mode and Instant 6.5.x for Instant mode.
So if you run ArubaOS 6.4.1.0 or higher in the 6.4.x release, you can operate those together. Version 6.4.4.20 is the latest release that you can run at the moment on the 650 controllers.