The Camunda Tools are available as an open source Community Edition licensed under the Apache License with a reduced feature set and an Enterprise Edition with more features. The Camunda Engine itself is the same in both editions. The differences only apply to the administration tools (Admin, Cockpit, TaskList, and Optimize) and in the availability of patch releases and customer support.
The workflow engine integrated into the ImageMaster standard assembly is always a version of the Community Edition. This means that the ImageMaster workflow integration can be used for testing, demos, and even for production without any license fees other than the ImageMaster BPM module itself. However, in production environments rather order the Camunda Enterprise edition to get access to the full feature set of the administration tools and to get customer support.