Gents,
I totally understand why you should have all controllers on the same firmware version, but I have the following problem.
We have two 3400 series controllers with another 2 years left before being up for replacement according to our equipment lifecycle. These controllers can only be upgraded to AOS 6.4.4.9.
The rest of our network is running 7000 series and we intend to upgrade to the latest stable version, we are buying 315 series access points to deploy and these need at least AOS 6.5.x to be managed by a controller.
These two 3400's are critical to business operation (highly mobile warehouse environment with failover between the two 3400s).
I need to upgrade to get the 315s to work, what would you propose?