---
upgrade:
  - |
    Starting with Yoga, Ironic has changed the default PXE from plain PXE to
    iPXE.
    Kolla Ansible follows this upstream decision but allows users to revert to
    plain PXE. Please note Kolla Ansible does not support plain PXE and iPXE at
    the same time - the user must choose one. For details, please refer to
    Kolla Ansible's documentation.