2. Namespace Requirements

Ensure your BPMN file includes these namespaces:

<definitions 
    xmlns="http://www.omg.org/spec/BPMN/20100524/MODEL"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:flowable="http://flowable.org/bpmn"
    xmlns:activiti="http://activiti.org/bpmn">

Note: Form properties use the activiti: namespace for compatibility with Flowable's form engine.