Just updated my production Indigo iMac to Big Sur and Indigo is working fine.
Not so good news is that my Zigbee2MQTT has gone pair shaped.
I am getting a message:
Error: Failed to connect to the adapter (Error: SRSP - SYS - ping after 6000ms)
Looking on Zigbee2MQTT related forums, a number of solutions are offered; None of which seem to have worked so far.
One solution I haven't been able to try yet is to reflash the CC2531 as I haven't got a programmer. Luckily, Amazon has come to rescue and I have ordered one for delivery tomorrow.
The CC2531 is seen by the Mac, can be written to and I have double checked that the port is correct. The green light comes on but as soon as I start NPM it goes out. So I think communication is taking place but not correctly.
I don't think the issue is with Big Sur per se, but the install probably triggered the situation.