MQTT Modules have been Sparkplug v3.0.0 compliant since the v4.0.14 module release
Sparkplug v3.0.0 Compliance - MQTT Modules for Ignition 8.x - Confluence and String and DateTime Arrays have been supported from our v4.0.13 release Ignition Datatypes Supported via MQTT - MQTT Modules for Ignition 8.x - Confluence
Thanks!