Our ZD1200 version is "10.4.1.0 build 257" and R720 version is "10.4.1.0.257" , now we have Lenovo T480 , T490 and T14 , the colleague who use T480 always complain the wifi signal are not stable , need to disconnect then connect again , but T490 and T14 colleagues not have this issue .
So what config in ZD or R720 should I modify to deal with this problem !!!!
It is most probably problem of adapter drivers. I have seen it with HP and Lenovo laptops.
Just one more possibility -- If your network uses WPA2-Perosnal (shared password) than you have to disable 802.11r and 802.11k (fast roaming). As windows laptops support fast roaming only with WPA-Entreprise (with Radius authentication) and only if hardware and drivers support it too. Unsupporting fast roaming devices may have different issues with enabled fast roaming -- from disconnects to even inability to connect at all.