MQTT Version issue

Our version compatibility matrix is here: Ignition Compatibility with Cirrus Link Modules - MQTT Modules for Ignition 8.x - Confluence

So, v4.0.13 Cirrus Link modules will run on the Ignition versions you are trying. It appears you may be hitting something else but I’m not quite sure what without more details. There were some changes in subscriptions between those versions. Maybe you’re hitting an issue with MQTT Server ACLs?

The quickest way to get to the bottom of it would be to open a support ticket here: Contact Support - Cirrus Link Solutions - Worldwide - United States

Including logs should help us get to the bottom of it quickly.