The decision when to roam is entirely up to the client radio driver and supplicant, and internal algorithms that analyze RSSI, interference and other factors. Ruckus smart-roam will not disconnect a client, but will withhold probe responses when we have determined that it's below reasonable RSSI and another AP sees it better. If
there is no better signal AP, the client will not be "encouraged" to leave. This is only
available on ZD managed APs however, as smart-roam is configured on the WLAN.
Apple updates are frequently resolving problems like iOS device stickiness, so *do*
update your devices when updates are made available.