I am running OH 2.4.0-1 on a Raspberry PI 3+ Raspian 8 Jessie
I Love OpenHab!
To support Zigbee I am using a Telegesis ETRX357-LRS Zigbee USB module. I was on the hunt for a Zigbee inline switch found this one on Amazon. This one is around $10 US and it works very well.
The switch works from 85 AC volts to 265 volts and supports 10 amps.
After installing the switch into my circuit, using Paper UI it posted to the OH inbox immediately upon power up. With Paper UI I was able to enable and configure the new ZigBee controller in only a few minutes.
There is another vendor on Amazon that has it for even less now, Zripool Zigbee On/Off Controller Smart Switch APP Remote Control Smart Home Zigbee Module AC85-265V 10A.
I have considered the Sonoff wifi switches as they are even less unit cost, but I am in the mode of trying 1 of everything to discover what will meet my needs best.