Let me describe the issue. The client has 2 ZD3000 series located somewhere in Antwerp Belgium. The customer has several sites and access points are installed at these remote locations (around 270 access points in total). The access points are a mix of ZF7372, R500, T300 and ZF2741). We have 2 sites where there are only ZF2741 access points installed. On Sunday, the client performed an upgrade from 22.214.171.124 build 15 to 126.96.36.199 Build 9, nothing else was changed to the config. This is when problems started to arise, especially at the sites with ZF2741 access points installed only. The affected client devices are all clients that connect to a ZF2741 using 188.8.131.52 build 9 (so not only scanners but laptops also). I see that the clients can authenticate - associate - 4-way handshake - receive an ip address and can send data (normal data, QOS data) and go to sleep. Nevertheless we see a lot of packet loss (around 85%) We see this if we do a ping from the ZD to the clients and from the APs to the clients. My best guess is that there is a new feature in 9.7 that causes these issues (like bandbalancing/steering/client load balancing?). If we rollback to 9.6 everything works just fine.