With "zigbee 3.0" being one of the most popular keywords in IoT these days, you may find yourself asking this - so, what IS zigbee 3.0?
The key motivation is to unify a number of zigbee profiles that emerged in the past few decades, some deployed more widely than others. Some examples are: Home Automation, Light Link, Smart Energy, Commercial Building, etc. Let us remind ourselves that we created zigbee profiles so that products coming from different device makers could talk in the same language. However, with the multiple profiles, we found ourselves still talking in different dialects.
With zigbee 3.0, the goal is to have "one profile that rules all". (All right, maybe not all the way there yet, as Smart Energy is not incorporated in zigbee 3.0.)
At the stack level, a zigbee 3.0 device must conform to revision 21 of the ZigBee PRO stack specification (what we usually call the R21 stack). Some of the new features in this revision include enhanced security (unique trust center link key, install codes) and mandatory end device aging mechanism. Our latest EmberZNet stack is fully R21-compliant and certified.
At the application level, zigbee 3.0 incorporates the Base Device Behavior specification (the common behavior of network commissioning), Green Power Proxy requirement (a zigbee 3.0 route device must be able to proxy Green Power frames), and the latest of the ZCL specification. We provide App Framework plugins that help you to be fully compliant to the zigbee 3.0 application requirements.
In the simplest term, think of zigbee 3.0 as the newest profile (that is both ZHA and ZLL, plus more) on top of the latest zigbee stack.
For some practical guidelines on moving your legacy ZigBee device applications to zigbee 3.0, and inter-operation between legacy and zigbee 3.0 devices, please review these posts: