From V6.6.2.0 release notes:
IMPORTANT: If your controller is not already running Version 5.7.5.0 or 6.0.3.0 or later, two-step upgrade must be performed. First upgrade your controller to Version 5.7.5.0 or 6.2.1.1, and then as a second step, upgrade the controller to V6.6.0.0.
I went from 5.7.4.x I think, to 6.2.1.1 and then 6.5.3.0. Later went to 6.6.2.0 and still there - No trouble.
Just remember that your AP software is upgraded everytime you upgrade the controller software.
Your safest bet is reading through the release notes to check that "your" config will not present a problem. They do change options between updates sometimes but it is well documented.