Overview
Understand QBits and the limits of 4.0 release compatibility.
What is a QBit?
A QBit is a reusable Java component that adds metadata and behavior to a QQQ host application. Its producer registers tables, processes, widgets, or customizers using component-specific configuration.
Compatibility is per component
QQQ 4.0 delivers the application, data, and extension template repositories. Existing production QBits are migrated separately. Do not assume a catalog item, old 1.x compatibility label, or a Maven dependency that resolves has been tested with 4.0.
Review the component's source, release notes, POM, LICENSE, NOTICE, and tests before adoption. Built-in backend/authentication/middleware modules and separately released QBits are different packaging choices.
See Installing QBits, Configuring QBits, and Creating QBits.