OTA firmware updates
OTA (over-the-air) updates let a smart home device’s firmware be upgraded by radio — fixing bugs, patching security, and sometimes adding features such as Matter support. Whether you can actually apply them depends on the platform: vendor hubs update their own brand automatically, while Matter, Zigbee2MQTT, ZHA, and Z-Wave JS each have their own OTA mechanisms with varying coverage.
OTA reach differs by protocol. Matter defines a standard software-update mechanism, but in practice most updates still flow through the manufacturer’s own app or ecosystem as of mid-2026. Zigbee OTA works well where the manufacturer publishes images — Zigbee2MQTT and ZHA maintain shared open indexes of them (IKEA, Hue via its bridge, and others), but many cheap devices never ship an update at all. Z-Wave JS can flash firmware for devices whose makers release files.
Firmware updates are not always upgrades from your point of view: some have removed features or broken third-party compatibility, and battery-device updates can take hours over a sleepy radio. Reasonable defaults: apply security-relevant updates on locks and anything internet-exposed promptly; for a stable sensor mesh, “if it isn’t broken” has merit.
| Zigbee mechanism | OTA Upgrade cluster 0x0019 — the device requests blocks, verifies, then applies |
|---|---|
| Matter mechanism | OTA Provider and Requestor clusters, with the image transferred over BDX |
| Z-Wave mechanism | Firmware Update Meta Data command class, mandatory since Z-Wave Plus certification |
| Mains device update time | Typically 5–20 minutes |
| Battery device update time | Hours — a sleepy radio moves an image in small, infrequent blocks |
| Coverage reality | Plenty of low-cost devices never receive a single firmware image in their life |
How each protocol moves an image
Zigbee does it with the OTA Upgrade cluster. The device periodically asks its coordinator whether a newer image exists for its manufacturer and image type; if one does, it pulls the file down in small blocks at its own pace, verifies it, and waits for an upgrade-end command before switching over. The images themselves are signed by the manufacturer, so a coordinator cannot invent firmware — it can only serve what the vendor published. Zigbee2MQTT and ZHA both maintain a shared index of those published images, which is how an IKEA or Hue device gets updated on a DIY platform with no vendor hub involved.
Matter defines a proper software update service: an OTA Provider node announces images, an OTA Requestor on the device asks for them, and the file moves over BDX. In principle this means your controller updates your devices. In practice, as of mid-2026, most vendors still push updates through their own app or ecosystem, and support for the Matter mechanism across controllers is uneven.
Z-Wave uses the Firmware Update Meta Data command class, which has been a certification requirement since Z-Wave Plus. Z-Wave JS and zwave-js-ui expose it directly and can flash any device whose manufacturer publishes a file — which, as with Zigbee, is the real constraint.
Battery devices are the hard case
A sleepy device wakes briefly, takes a few blocks, and goes back to sleep. Moving a 200 KB image that way can take several hours, and the whole time the radio is doing far more work than its duty cycle was designed around. It is normal for a firmware update to visibly dent a coin cell, and not unusual for a device with a weak battery to fail partway through.
Practical consequences: replace the battery before updating a sensor that has been in service for a year, do not start an update on a device you need working that evening, and expect some devices to require a manual wake — pressing the pairing button periodically — to make progress. Locks and thermostats with larger batteries handle this much better than coin-cell sensors.
An interrupted update is usually survivable, because most implementations only switch to the new image after it has been fully received and validated. Usually is not always, and a device that loses power at the wrong moment can end up needing a physical recovery you may not have the tools for. Stable power matters most on mains devices being flashed during a storm.
When updating is a bad idea
Firmware updates are changes, not improvements, and the smart home has a track record. Updates have removed local APIs, disabled third-party integrations, changed the exposed attributes a platform depends on, added account requirements, and occasionally degraded battery life. A device that has run flawlessly for two years on a sensor mesh has nothing to gain from a version bump and something to lose.
The sensible split is by exposure. Update promptly anything that touches the outside world or guards a door: hubs, cameras, locks, anything with a cloud account. Leave alone the sensors, buttons, and bulbs that live entirely on a local radio, unless the release notes fix something you are actually experiencing. Read what the release changes before applying it, and look for a week of community reports on any major version.
Two operational rules save grief. Back up your coordinator or hub configuration before a firmware campaign, since a device that re-enumerates after an update can lose its identity in your automations. And never update the coordinator firmware and a batch of devices in the same session — when something breaks, you want one variable to blame.
Frequently asked questions
Do smart home devices update their firmware automatically?
It depends entirely on the platform. Vendor hubs — Hue, Aqara, IKEA, SmartThings — generally update their own devices automatically or with one tap. DIY platforms make it manual: Zigbee2MQTT, ZHA, and Z-Wave JS all show available images and let you decide. Many cheap devices have no update path at all, because the manufacturer never published one.
Can I update Zigbee firmware without the manufacturer’s hub?
Yes, where the manufacturer publishes signed images. Zigbee2MQTT and ZHA maintain a shared index of published firmware and can serve it from your own coordinator — IKEA and several other brands are well covered. What you cannot do is create firmware; if the vendor never released an image, no coordinator can update that device.
Does Matter handle firmware updates?
The specification defines an OTA mechanism using Provider and Requestor clusters, so in principle your controller distributes updates. As of mid-2026 most manufacturers still route updates through their own app or ecosystem instead, and controller support for the Matter mechanism varies. Assume you will still need the maker’s app for firmware on most Matter devices.
How long does a battery device firmware update take?
Hours, commonly two to eight. Sleepy devices only accept blocks when they wake, so the transfer proceeds in bursts. Fit a fresh battery first, do not start one on a device you need that day, and be prepared to wake some devices manually with the pairing button to keep the transfer moving.
Should I update my smart lock’s firmware?
Yes, more readily than anything else in the house. Locks are the device class where a security fix is worth the disruption, and they usually have enough battery to complete the transfer safely. Do it with fresh batteries, with the door open, and when you have time to deal with a re-pair if the update resets the device.