Pre-migration details

This guide describes how to migrate process solutions developed for Camunda 7 to run them on Camunda 8, including:

• Differences in application architecture
• How process solutions can be migrated
• How migration can be very simple for some models, but also marked limitations, where migration might get complicated
• You need to adjust code that uses the workflow engine API
• How you might be able to reuse glue code
• Tooling that can help with migration
• The Clean Delegate approach, which helps you write Camunda 7 solutions that are easier to migrate

note

We are currently developing improved migration tooling and will overhaul this guide around the 8.7 release. If you embark on a migration journey, please reach out to discuss your use case with us.

What to expect

Before diving into concrete steps on migrating your models and code, let's cover some conceptual topics and migration readiness steps. The list below provides an outline of the sections in this guide:

• Conceptual differences
• Migration readiness
• Adjusting BPMN models
• Adjusting DMN models
• Adjusting source code

Open issues

As described earlier in this guide, migration is an ongoing topic and this guide is far from complete. Open issues include the following:

• Describe implications on testing
• Discuss adapters for Java or REST client
• Discuss more concepts around BPMN: Field injection that is using camunda:field available on many BPMN elements. Multiple instance markers available on most BPMN elements. camunda:inputOutput available on most BPMN elements. camunda:errorEventDefinition available on several BPMN elements.
• Discuss workload migrations (operations)
• Eventual consistency

Reach out to us to discuss your specific migration use case.