I have wlan(clients)+eth(uplink) in a bridge.

Before 7.14 the forwarding between them (eth<->wlan) was working with default-forwarding=off, set on the wlan interface.

How do I set wlan client separation on 7.14?

Not sure if isolation has the same function, on the datapath you can set client-isolation on or off.
https://help.mikrotik.com/docs/display/ ... properties