In case you wanted the exact wording, here it is:
All initiating classes have the ability to swap maneuvers for newer ones as they level up. This is meant to work off of initiator level, rather than class level. In the Maneuvers section of each initiating class, replace
“Upon reaching 4th level, and at every even numbered initiator level thereafter (6th, 8th, 10th, and so on)” with
“Upon reaching initiator level 4th, and at every even numbered initiator level thereafter (6th, 8th, 10th, and so on)”. The bolded text has been changed.
Since prestige classes advance the initiator level of the previous class, this applies to them as well.