---
upgrade:
  - If upgrading with pre-icehouse stacks which contain resources that create
    users (such as OS::Nova::Server, OS::Heat::SoftwareDeployment, and
    OS::Heat::WaitConditionHandle), it is possible that the users will not be
    removed upon stack deletion due to the removal of a legacy fallback code
    path. In such a situation, these users will require manual removal.