Colin, Thanks for the response. I figured that would be the best answer for this situation. The problem is that I purchased this unit from a failed company liquidating their assets. I saw that both Aruba and Dell offer Lifetime Hardware Warranties on these units (as a personal safety net) - and I already have a MC 800-US-4 with AP-105 (x 4) in my lab. I was planning on replacing the EOL'd 800 with a newer (still supported) 650. This 650 unit had LIC-4-AP and LIC-2-AP already installed. Unfortunately, I am now finding that the 650 hardware warranty does not appear to be transferable. The unit failed shortly after I tested it out, and accepted ownership - I doubt Dell would allow purchasing a support contract post failure. Even If they did, I doubt they would transfer the 6 AP licenses over to the unit - so that would be another ~$300 just to get the same functionality as I have with the 800 controller - but with the added ability to use the WebUI with FireFox past v45.3.
Oh well, I was hopeful to be able to use a version of AOS beyond v5.0.4.18 in my lab, but I guess I just have to make this old hardware survive a few more years.
Thanks again for the response!