Location:

• http://docs.camunda.org/7.3/guides/migration-guide/#migrate-from-camunda-bpm-72-to-73-migrating-a-shared-process-engine-setting
• http://docs.camunda.org/7.3/guides/migration-guide/#migrate-from-camunda-bpm-72-to-73-migrating-an-embedded-process-engine-setting
  Phrase > The reason is that a 7.2 engine may not be able to execute process instances that have been previously executed by a 7.3 engine.<

Problem:
Customer understands that it is not possible to execute instances with 7.3 engine that where started with 7.2 engine.