Zigbee's sub-GHz sibling opens for certification: what Suzi means for coordinators

On September 2 the Connectivity Standards Alliance opened its product certification program for Zigbee sub-GHz, which it brands Suzi. Suzi extends Zigbee’s mesh onto bands below 1 GHz, which the Alliance describes as 800 MHz in Europe and 900 MHz in North America, while 2.4 GHz Zigbee carries on as before. The pitch is longer range and better penetration through walls. It arrived with Zigbee 4.0 in November 2025, and certification was meant to open in the first half of this year. Here is what it does and does not mean if you were about to buy a Zigbee stick.

Short version: buy the coordinator you were going to buy. The Alliance is explicit that Suzi extends Zigbee’s 2.4 GHz operation rather than replacing it, and that it is designed to work alongside existing networks. It needs a radio that can transmit below 1 GHz, and every Zigbee stick I recommend is built on a 2.4 GHz Zigbee chip, my own Connect ZBT-2 included. The first certifications that have been reported went to software stacks rather than devices. The Home Assistant side has an open feature request and no implementation. None of the coordinators I recommend becomes obsolete because of this, and I couldn’t find a Suzi device on sale to wait for.

What was announced

Two announcements, about nine and a half months apart.

In November 2025 the Alliance announced Zigbee 4.0 together with Suzi. Zigbee 4.0 is the security and commissioning release: dynamic link keys, a device interview step, restricted mode, trust center swap-out, Zigbee Direct for Bluetooth onboarding without a hub, and Coordinated Sample Listening so battery devices can talk to each other. The Alliance says it is fully backward compatible with Zigbee 3.0 and Smart Energy.

Suzi is the other half: optional physical layers below 1 GHz, sitting alongside 2.4 GHz rather than in place of it. September’s news is only that manufacturers can now put sub-GHz Zigbee products through certification. What the Alliance claims for it is range, wall penetration, resilience in crowded radio environments and fewer repeaters for a given area. It gives no numbers for any of that, and while it lists residential use cases, the deployments it describes are buildings, campuses, outdoor spaces and industrial sites.

One detail matters more than the rest. The Alliance says Zigbee supports bridge devices operating across both 2.4 GHz and sub-GHz radios, so a network can be extended gradually and installed devices keep working. That is the opposite of a forced migration.

Who is certified so far

Per IoT Insider, Exegin Technologies, a Vancouver mesh-networking software house, is one of the first two stack vendors certified, and its chief executive is vice chair of the Alliance task group that wrote Suzi. What passed certification is a software stack. IoT Insider names no chip, module or finished device, and its own conclusion is that wider adoption waits on compatible silicon, modules and end devices.

What stays local, and what this needs

Suzi is a radio layer, so nothing here moves anything to or from the cloud. The local question is narrower: can the hardware in your house ever speak it, and can Home Assistant drive it?

Your coordinator cannot do this, and that is fine

Sub-GHz needs a radio that transmits below 1 GHz. Here is what the Zigbee sticks I cover are built on.

There is one near-miss. TI’s CC1352P, a chip Zigbee2MQTT’s adapter guide treats as equivalent to the CC2652, covers both sub-1 GHz and 2.4 GHz and can run them concurrently. Zigbee2MQTT’s own documentation notes the CC1352’s sub-1 GHz capability and then dismisses it: not relevant for Zigbee, which uses 2.4 GHz, and no difference between the CC1352 and the CC2652 for Zigbee2MQTT’s purposes. So even where the silicon exists, I couldn’t find anywhere that says a Suzi firmware or host-side support exists for it. I cover no CC1352 coordinator, so this changes nothing in my catalog either way.

Home Assistant support is still a request

The Suzi request against ZHA was opened in November 2025 and is still open, with no implementation and no roadmap. It asks the questions that come first: whether dual-band can live on one network, and whether ZHA should manage two Zigbee networks on one adapter. In the zigpy discussion, a maintainer flagged the same unknown from the protocol side, whether a dual-frequency router can relay between the bands at all. Zigbee2MQTT’s adapter page does not mention Suzi or Zigbee 4.0.

There is a hardware request too, for a dual-band coordinator along the lines of a future ZBT-3. It has been open since November 2025. As of the last replies I read, in April, I couldn’t find any commitment from Nabu Casa, and one participant argued against putting Suzi into a mainstream stick before production implementations settle. The person who filed it frames it as a request for tinkerers and small builders, not for the shelf.

Buy, wait or ignore

Home Assistant house. Ignore Suzi and buy now. The ZBT-2 stays my default, the ZBDongle-P stays the value pick, and the SLZB-06 stays the answer when placement is the problem. None of them becomes worse because a new band exists, and I couldn’t find Suzi support in ZHA or Zigbee2MQTT that would use that band. If you want the range Suzi promises today, the lever that exists is mains-powered Zigbee routers and better coordinator placement, not a new radio.

Apple or Google Home house. Nothing to do. Suzi is a Zigbee feature, and these platforms reach Zigbee through a hub or bridge. Whether it ever surfaces depends on what hub vendors ship, and I couldn’t find one that has said anything about it.

Budget buyer. Do not defer a coordinator purchase over this. Certification opening is the start of a long cycle: silicon, then modules, then devices, then the open-source stacks. A stick bought this week will be doing its job long before a Suzi device sits on a shelf next to it.

Does this change my picks?

No, and I want to be clear about why rather than just asserting it.

• Best Zigbee coordinators. Unchanged. All three picks are 2.4 GHz silicon, which was true last month and is not a defect now. The one thing I will add to that page in a later pass is a line saying sub-GHz needs a different radio, so nobody reads a Suzi headline as a reason to hold off.
• Zigbee vs Z-Wave vs Matter vs Thread. The comparison holds. The page’s summary of where each protocol sits is about hardware you can buy, and I couldn’t find a Suzi device on sale. When there is a device to weigh, that page is where the sub-GHz row belongs. It is not a pick change now.
• No catalog product is superseded. Nothing in the announcements marks any coordinator as end of life, and the Alliance’s bridge-device language points the other way.

If a dual-band coordinator is announced with a Home Assistant path, that is a different story and it gets its own page.