Zigbee 4.0 pivots to sub-GHz mesh

Zigbee 4.0, accompanied by its sub-GHz counterpart "Suzi," aims to solve the 2.4 GHz congestion issues by utilizing the 800 MHz and 900 MHz bands in Europe and North America respectively. This frequency shift allows signals to penetrate walls and foliage more effectively, increasing range and reducing interference. Suzi-enabled devices will particularly benefit outdoor smart homes, garages, and large multi-story installations. This update focuses on improving network reliability and security. Zigbee 4.0 includes features like advanced frame-counter synchronization to prevent replay attacks, unique link-key monitoring, and improved Trust Center handling. These enhancements ensure devices maintain secure connections and can rejoin networks, even in complex environments. The new standard maintains backward compatibility with Zigbee 3.0 and Smart Energy devices, ensuring existing devices will continue to function. Upgrading to a Zigbee 4.0 hub will grant access to new features like BLE onboarding and batch commissioning, simplifying device integration. However, to use Suzi's sub-GHz capabilities, new multi-band coordinators that support both 2.4 GHz and 900 MHz are necessary. The Suzi certification program is expected to launch in the first half of 2026. Suzi is built on the Zigbee network layer, but uses long-range modulation to support large-scale networks. ABI Research forecasts strong growth in the smart home device market, expecting shipments to grow from 880 million in 2023 to 1.5 billion by 2030.