---
upgrade:
  - |
    The ``CoreFilter``, ``DiskFilter`` and ``RamFilter``, which were
    deprecated in Stein (19.0.0), are now removed. ``VCPU``,
    ``DISK_GB`` and ``MEMORY_MB`` filtering is performed natively
    using the Placement service. These filters have been warning
    operators at startup that they conflict with proper operation of
    placement and should have been disabled since approximately
    Pike. If you did still have these filters enabled and were relying
    on them to account for virt driver overhead (at the expense of
    scheduler races and retries), see the `scheduler`_ documentation about
    the topic.

    .. _scheduler: https://docs.openstack.org/nova/latest/admin/configuration/schedulers.html#hypervisor-specific-considerations
