The Connectivity Standards Alliance has officially announced Zigbee 4.0, a significant evolution, with three very clear axes: improved security, simplified pairing, and above all, the opening up to sub-GHz frequencies in Europe and North America. In practice, Zigbee aims to maintain what has made it successful in home automation while addressing several well-known limitations, particularly in terms of range, reliability in congested environments, and large-scale deployment.

A Zigbee 4.0 that is no longer limited to 2.4 GHz

This is the point that immediately grabs attention. Until now, in the minds of many users, Zigbee was almost synonymous with 2.4 GHz. However, the CSA indicates that Zigbee 4.0 adds support for a European PHY at 800 MHz and a North American PHY at 900 MHz. The goal: to gain in range, coverage, and radio robustness, especially in complex buildings or for broader use cases.

On the ground, the interest is evident. Lower frequencies generally penetrate obstacles better than a saturated 2.4 GHz network burdened by Wi-Fi, Bluetooth, and numerous other devices already using this frequency. For outdoor sensors, outbuildings, garages, large homes, or certain tertiary buildings, Zigbee 4.0 thus opens up a very interesting perspective. This is also what the CSA highlights with Suzi, the new brand associated with the sub-GHz part of the Zigbee ecosystem, designed for long-range, low power consumption, and interoperable operation between brands.

The CSA speaks of European “800 MHz” and North American “900 MHz” support, similar to what Z-Wave has been offering for a long time. However, the CSA does not precisely detail the specific channels to be used in each region. It is therefore better to avoid stating today that Zigbee 4.0 will use exactly the same frequencies as any other protocol. We know it falls into the same large sub-GHz radio family, but we do not yet have the exhaustive detail of the final channels for end products.

The real innovations of Zigbee 4.0: security, reliability, and commissioning

The other major area of focus for Zigbee 4.0 concerns security. Silicon Labs summarizes several important developments. Among these are the Dynamic Link Keys, which enhance key negotiation during integration and also allow for key rotation after updates. The protocol also adds a “device interview” mechanism, allowing the Trust Center to examine the capabilities of a device before granting it access to the network. The idea is to better control who connects, how, and with what level of trust.

The network resilience has also been reviewed. Zigbee 4.0 brings advanced synchronization of APS frame counters to limit replay attacks and better manage restarts or outages. It also adds a new TLV encoding format, enhanced routing protections, standardized and enabled retry network mechanisms, as well as more reliable polling for battery-operated devices. This is not the kind of innovation that excites on a marketing sheet, but in home automation, it is exactly the type of improvement that matters: fewer message losses, less strange behavior, and a cleaner network.

Another very interesting point: the “Trust Center Swap-Out.” Silicon Labs’ documentation explains that Zigbee 4.0 allows for easier replacement of the main controller of a network without needing to recommission everything. For advanced users, integrators, and fleet managers, this is far from trivial. Changing hubs or replacing a coordinator becomes potentially less painful.

Finally, Zigbee 4.0 also improves energy efficiency. The protocol introduces an evolution of Coordinated Sample Listening (CSL), which allows battery-operated devices to sleep more while remaining synchronized. For sensors, probes, or small autonomous devices, this can translate into better autonomy without degrading network responsiveness.

Zigbee Direct: simpler pairing thanks to Bluetooth LE

The most visible novelty for the end user is undoubtedly Zigbee Direct. The CSA and Silicon Labs explain that this feature allows the use of Bluetooth Low Energy for commissioning and control, with a smartphone or tablet, without relying on the traditional integration pathway through a hub for each interaction. In short, integration can become smoother, more accessible, and less intimidating for both the general public and installers.

However, caution should be exercised not to overinterpret this announcement. Zigbee Direct does not mean that the entire classic Zigbee architecture will disappear overnight, nor that every Zigbee 4.0 device will function without any gateway in all scenarios. What the chip manufacturer indicates is that Bluetooth LE simplifies commissioning and some interactions, thereby reducing installation friction. This is already significant, especially in light of a recurring complaint about Zigbee: being technically very good but sometimes a bit less straightforward to grasp than other more “plug and play” solutions.

For professional deployments, Zigbee 4.0 also adds batch commissioning, allowing the addition and configuration of multiple devices simultaneously. In pure residential applications, this might not be the number one argument. However, for collective lighting, small tertiary sectors, connected buildings, or installer projects, it represents a real time saver.

Compatibility with existing systems: good news on paper, caution in real life

The good news is that Zigbee 4.0 is announced as fully backward compatible with Zigbee 3.0 and the Smart Energy profiles. The CSA even talks about continuity with over a billion Zigbee devices already deployed, and Silicon Labs specifies that the Zigbee 3.0 certification remains valid for at least 18 months to ensure a smooth transition. In other words, Zigbee 4.0 is not presented as a brutal break from the ecosystem.

However, it is essential to be nuanced right away. This backward compatibility does not mean that all existing equipment will suddenly benefit from sub-GHz or all the new functions magically. To gain access to the new 800/900 MHz radio bands, compatible hardware at the radio level will be necessary. An existing 2.4 GHz Zigbee dongle will not become a sub-GHz coordinator through mere software update if its hardware does not include the necessary radio. This is an unavoidable physical constraint. This conclusion is a logical technical deduction based on the addition of new radio PHYs and the fact that manufacturers are already announcing SDKs and hardware “Zigbee 4.0 ready.”

Another point to keep in mind: the compatibility of the ecosystem will also depend on concrete implementations. Between a published specification, compatible chipsets, coordinators actually marketed, and then integrations into Home Assistant, Zigbee2MQTT, or market gateways, there is always a slight delay. Silicon Labs indicates that it is ready on validation and SDK support, but that does not yet mean that the entire public ecosystem is already mature today.

In short, there is no need to panic for the existing. Zigbee 3.0 networks do not become obsolete overnight. However, future generations of gateways, USB coordinators, and radio modules will gradually open access to the benefits of Zigbee 4.0. For enthusiasts of Home Assistant, this is primarily a subject to keep a close eye on regarding upcoming dongles and controllers.

The parallel with Z-Wave: yes, Zigbee is clearly moving closer to its playing field

It is impossible to talk about Zigbee 4.0 without mentioning Z-Wave. Historically, one of Z-Wave’s significant advantages was its operation in sub-GHz. In Europe, this protocol has notably used frequencies 868.4 MHz and 869.85 MHz depending on regions and uses, allowing it to long since avoid the crowded 2.4 GHz band.

With Zigbee 4.0, Zigbee is clearly stepping onto Z-Wave’s turf on this specific point. The protocol maintains its low-power mesh network logic but now seeks to offer better range and radio penetration via sub-GHz as well. Viewed this way, yes, the parallels are clear. Zigbee recovers part of the historical argument of Z-Wave.

Does this mean that Zigbee 4.0 and Z-Wave will use “the same frequencies”? Precision is needed: they are getting closer in terms of operating band, as both are discussed as sub-GHz, but the consulted official sources do not allow us to definitively affirm that they will share exactly the same radio channels in Europe. The CSA talks about a European 800 MHz PHY for Zigbee 4.0, while the official Z-Wave references mention 868.4 MHz and 869.85 MHz in Europe. So the correct summary today is: same family of frequencies, same promise of better range than in 2.4 GHz, but not enough public elements to say “it’s strictly identical.”

There is also a difference in philosophy to keep in mind. Z-Wave remains very focused on a specialized home automation ecosystem, with historically regulated interoperability. Zigbee, on the other hand, remains broader, larger in volume, very present in lighting, sensors, low-cost objects, and benefits from an immense installed base. If Zigbee 4.0 delivers on its promises, it could thus combine two worlds that until now seemed quite separate: the price and spread of Zigbee, with some of the radio advantages that were willingly associated with Z-Wave.

What Zigbee 4.0 can really change in a connected home

For the end user, the most tangible benefit may not necessarily be visible on the product box but in daily behavior. More stable sensors, better outdoor range, a network less sensitive to a congested Wi-Fi, a less painful controller replacement, simpler pairing with a smartphone… said like that, it sounds almost mundane. And yet, it is exactly what can make the difference between a pleasant connected home and an installation that becomes frustrating after three weeks.

In a large house, a garden with an outbuilding, a distant gate, a technical room for a pool, a shelter, or a workshop, Zigbee 4.0 could become much more relevant than before. In small tertiary sectors as well, with their rapid deployment needs and stability search, the benefits are quite clear. The CSA also positions Suzi for residential and commercial uses, not just for the pure consumer smart home.

One should not too quickly dismiss the current Zigbee 3.0. The installed base is immense, the products are numerous, prices remain attractive, and integrations into Home Assistant or Zigbee2MQTT are today very matured. Zigbee 4.0 should therefore be seen less as a brutal replacement than as a gradual upgrade of the standard.

Should you wait for Zigbee 4.0 before buying Zigbee?

Not really. For someone equipping their home today, Zigbee 3.0 remains a very relevant choice, especially since Zigbee 4.0 is announced as backward compatible and the transition will be gradual. Waiting for a hypothetical complete switch doesn’t make much sense, especially since the actual Zigbee 4.0 product offering on the market will take some time to structure.

On the other hand, for an installer, manufacturer, or advanced user preparing a multi-year project, Zigbee 4.0 clearly changes the game. It puts Zigbee back in the running on long-range, robustness, and modern commissioning issues. And here, frankly, the movement deserves to be followed very closely.

In the end, Zigbee 4.0 does not bury either Zigbee 3.0 or Z-Wave. But it seriously reshuffles the cards. The standard corrects several historical weaknesses without breaking the existing ecosystem, which is probably the best news of this whole announcement. What remains now is the most important: to see the first concrete products, the first compatible coordinators, and the first truly usable integrations on the ground. That’s where everything will be decided.