Product and Software: This article applies to all Aruba controllers and ArubaOS versions.
When mixed mode (AES + TKIP) is used, the AP uses TKIP for group key encryption.
Historically, AES clients should understand TKIP but not the other way around. However, clients are free to choose AES or TKIP for unicast traffic. All unicast keys are unique on a per client basis. This is why most clients connect with AES for unicast but accept TKIP broadcast from the AP.