It is now Monday, I ugraded one of my Controllers last Thursday(I am sure glad we have a failover - 2nd Controller - did not upgrade) to 4.1.171. I went from 22.214.171.124 to 4.0.217 before going to 4.1.171. I also did both aes files in the 4.1.171 upgrade. After the upgrade, I moved some of our AP's to the upgraded Controller, All APs downloaded the new firmware. All was fine for a day, then I started noticing a lot of connections to a couple APs, which was out of the ordinary, but let it go since it could be normal. Over the weekend our Network started to become erratic and Network connectivity became unstable. We would lose Server/Switch Connections throughout the Network. On Sunday, we disconnected the upgraded controller and all the APs failed over to the un-upgraded one and our network went smooth again. Today (Monday), I downgraded to 4.0.217 and am testing with a single AP and it all seems smooth. Am I the only one that had problems with the latest upgrade? Please some input.