Environment- This articles applies to Aruba Controller models 3200XM and 3400.
Answer- Some features even though they come built-in with the new ArubaOS version, still have to face the restrictions based on the Aruba Controller models that they get installed on. One such feature that come integrated with ArubaOS 6.3 is AP Image Preload.
AP Image Preload is not supported on 3200XM and 3400 controller models.
As you see below screenshot, the controller throws an error when we try to activate the feature: