HOW does it improve Wi-Fi reliability? I've seen phrase used for the last 3 updates and Wi-Fi is still unstable on OS X 10.11

Aruba (Wireless AP company) confirmed that a bug in Apple concerning Wi-Fi was supposed to be fixed in El Capitan 10.11. I've seen Wi-Fi reliability be a common issue with these releases. And I still experience wifi roaming and wireless ethernet power save issues up to El Capitan 10.11.1. Are there more details about this Wi-Fi issue that Apple keeps trying to solve?