I know Zwavejs2Mqtt can perform a firmware update, but I can’t find the firmware update anywhere so far. Anyone accomplished this or know where to find it?
No idea then, I don’t have the devices. If no one else responds, you can ask for help at node-zwave-js discussions, they might be able to figure out how to extract the firmware, or provide a fix to support that file format. It seems similar to the Aeotec exe upgrades, which are supported.
Or you can try to use the updater tool itself. I’m not familiar with how it works.
You can contact Leviton support and try to get the actual firmware files (*.ota) as other users have had success doing, or possibly wait for that exe format to be supported. https://github.com/zwave-js/node-zwave-js/issues/4101