AFAIK open/close and on/off are basically the same. And yes, they did it with the on/off (I noticed this after I updated mine to the latest firmware).
Same with the 5 button remote (IKEA E1524/E1810 control via MQTT | Zigbee2MQTT) - tested myself. Not sure about styrbar. I just tested unicast binding and it worked, but did not test group binding
See Ikea 5 Button Switch on 24.4.5; Dimmer on 24.4.6 - group bindings don't work anymore - #4 by Mimiix btw