200.9 has been released, you can find it from the below link. All Wi-Fi 5 Wave 2 (802.11ac wave 2) APs are supported plus 6 new Wi-Fi 6 APs are supported too.
An R610 that I just installed had me update to 200.9... but then the R510s that were to follow won't update... Reverting R610 back is taking forever... been updating for nearly 45 minutes.
What is the current version of R510 APs, are these working in the existing network and you are just trying to add R610 to the Unleashed network? How many R510 APs do you have and facing the issue?