I noticed that after updating my Homey Pro 2026 to Homey OS v13.5.0, the Zigbee firmware has also been updated.
From:
To:
The Homey OS change log does mention ‘updates various components to the latest version’ and ‘various minor improvements’ related to Zigbee.
Does anyone have any idea of what has or should have improved?
Don’t know, but maybe this help?
https://docs.silabs.com/sisdk-release-notes/2026.6.0/sisdk-zigbee-release-notes/
I love how communicative Athom is! 
Yeah compared to HA, the firmware updates are communicated so poorly
Look at how successful it is for HA to have content creators like Lewis Barclay from Everything Presence and Simon from Byte of Geek putting out monthly videos.
It wouldn’t take a lot of effort to partner with someone for this, such as Patrick Hunt from Make Smart Matter. He uses Homey a lot.
I did some digging into the Zigbee firmware change in Homey 13.5.0.
The interesting part is that this appears to be indeed a much bigger change than the Homey changelog suggests - but that’s normall, I haven’t ever seen any notice about update of firmware chip (and there are actually few of them) - I believe it’s just Athom’s approach to ensure that when issues are reported, they are not reported in the way “I saw you changed firmware and gues what - now NOTHING works” … 
On Homey Pro 2026, the Zigbee firmware moved from 7.4.2-0 to 9.1.0-0, which means a significant jump in the underlying Silicon Labs EmberZNet/Zigbee stack.
Looking (with AI help) at the Silicon Labs release notes between those versions, the more relevant improvements include:
**Improved APS reliability, including APS acknowledgements (ACKs), means Homey can get end-to-end confirmation that a Zigbee command actually reached the target device’s APS layer—not just the next router—so failed deliveries can be detected and retried more reliably.
Network steering / joining fixes, including a fix that specifically improves join success on larger Zigbee networks.
Rejoin and recovery improvements, especially around Trust Center connectivity.
**BDB 3.1 / Zigbee PRO R23 groundwork adds newer Zigbee security and recovery mechanisms, including Dynamic Link Keys for stronger per-device trust, APS frame-counter synchronization to avoid communication failures after resets or desynchronization, and improved Trust Center/rejoin handling for more robust network security.
Routing-related improvements and more configurable route-table handling.
Green Power fixes, including commissioning and proxy/sink table handling.
Security-storage fixes, especially around key migration and secure key storage.
Better handling and diagnostics around RSSI/LQI/channel information at stack level.
One important caveat: these are capabilities and fixes in the Silicon Labs 9.1 stack. That does not automatically mean Athom enabled every new feature in Homey’s firmware. In particular, I would not interpret this alone as “Homey now supports Zigbee 4.0, despite :
Silicon Labs states for SDK 9.0:
“Zigbee 4.0 compliance with BDB 3.1 and R23 support”
From a practical Homey perspective, the most interesting expected benefits are probably:
1. Better command delivery reliability
2. Better pairing/joining, especially in larger meshes
3. Better rejoin/recovery behaviour after network disruptions
There is also already a Silicon Labs 9.1.1 release, which contains additional improvements for sleepy end devices and APS retry timing, while Homey currently appears to use 9.1.0-0. … so let’s see few months I gues until we get there
It would be useful if Athom could confirm which of the new stack features are actually enabled/configured in the Homey NCP firmware, and whether Homey Pro 2023 receives the same Zigbee firmware image/version as Homey Pro 2026 but maybe it will come simply with “Zigbee 4.0 support” … .
So, in short: this does not look like just a minor radio firmware refresh. The jump from 7.4.x to 9.1.x brings a substantial amount of Zigbee stack development, even if only part of it may be exposed or used by Homey today.
Currently I’m happy to report that so far my 86 Zigbee devices still works fine.
Thanks for your analysis! 
I also checked the link that @Mike_Nono provided up in this thread, but I have to admit that most of the change log is too technical for me 
.
It is difficult to translate into what it actually means in the real world from an end user’s perspective and/or what problem it fixed.
It would be a credit to Athom if they would provide more specifics in their change log (in plain language). Though I can also understand that they probably wanted to prevent getting too technical and summarized it as ‘various updates’.
I can confirm that Homey Pro 2023 also got its Zigbee firmware updated to 9.1.0-0
No such luck for me, all my ~60 zigbee devices (Ikea, Aeotec, Aqara, Namron) lost connection after the update. I can get them back by doing “Repair” on each device and re-bind, but it’s a lot of work 
Some devices are really inaccessible in our house. Anyone got any idea of a quicker fix?
How long did you wait after the update? The Zigbee mesh needs to be rebuild again.
What if you restart your Homey and wait a bit. Does that help?
In parallel open ticket to Athom with the debug log attached. What does the state in Developer interface shows you in Zigbee section ? I guess you tried ordinary things, restart, reinstalling the same firmware etc.
That post relates to a Matter device.
Does that procedure also work for Zigbee devices? I have not seen such an update button after interviewing a Zigbee device in the past, but that might have changed in a recent firmware update.
Nope.
You are 100% right, I was thinking of thread.
Sadly zigbee does not have anything like that
Yes that’s annoying. (unknown node) It just sits there.
And all you can do on homey is to restart / reboot homey. (as far as I know)
If you could restart the zigbee module on it’s own it should be great.
Or just a delete function
@SunBeech @Sharkys the update was ~4 days ago, restart didn’t help (both soft and hard restart), and the mesh should have rebuilt itself by now. I’ve been adding back in nodes in the hope that it would cause a rebuild of the whole network, but dead nodes are still dead.
I also opened a ticket with Athom, an the response is basically “you have to repair each node yourself”. As i understand it, the binding data that is stored in the zigbee radio was lost during the update.
Doing a backup restore will not work either.
They did forward my zigbee dump to the dev team.
Looks like I have to find the ladder and just do the work of repairing all the devices by hand.
That’s very unfortunate. I completely understand your feelings, based on my experience after a Zigbee reset: I have approx. 75 Zigbee devices and some switches are built into the wall socket. Well, at least you have something to do the coming days…
None of my varoius brands Zigbee devices dropped after the update. All of them are connected and working as expected
From what I can see in your screenshot, all the routers are offline.
Can you repair one or two router’s closest to homey, and see if it start to rebuild?
