I just found out that the EM35x will no longer be supported by zigbee due to the 256k flash limit
As I was thinking to get a new one for a while, I wonder what the best option to buy will be?
Again a USB stick attached to the PI4 or an external hub (I have an Tradfre hub, but I don’t think I can use it?)
True, but that is to allow it to add new features in future - ie for the new requirements that are soon going to be added to the standards. It doesn’t mean that it will not continue to work very well with all current features.
Also note that the binding supports the newer Silabs chips as well - they generally work the same from the binding perspective.
Personally, I’d still highly recommend the Silabs chips as that is what all my commercial customers are using so it gets the most testing etc.
Out of the box that’s true, there are some firmware available that does implement ZB3.0, but note that this is also not supported any longer by the manufacturer (ie Texas Instruments).
Yes, the binding will support ZigBee 3. However, note that a large part of this is actually implemented by the dongle, and not the binding. Many of the advanced features are only available currently with the EM35x / MG chips (ie Silabs).
If your going down the hub route I have just published a binding for sonoff. Their zigbee hub is 3.0 and although not integrated yet I have one turning up tomorrow (love Amazon) so it will be present very soon. I’m not sure what it will support but I have a couple of items that don’t work with the zigbee binding and my usb stick so took a punt as it’s only cheap (£15 on eBay).