Wow MDK5 5.11a what a mistake.
I just tried working with a couple of different projects from MDK4, just to see how things go. One built and compiled fine in 5.10 and hopelessly fails in 5.11a. The other was never going to work in both. I tried working through some of the errors and windows to try to convert the projects.... waste of my time. Sticking with mdk4 until Keil figures things out. I don't have time to be a unpaid guinea pig for ARM.