---
prelude: |
    The 25.0.0 release includes many new features and bug fixes. Please be
    sure to read the upgrade section which describes the required actions to
    upgrade your cloud from 24.0.0 (Xena) to 25.0.0 (Yoga).

    There are a few major changes worth mentioning. This is not an exhaustive
    list:

    - The latest Compute API microversion supported for Yoga is `v2.90`__ (same
      as the Xena release).

      .. __: https://docs.openstack.org/nova/latest/reference/api-microversion-history.html

    - Experimental support is added for Keystone's `unified limits`__.
      This will allow operators to test this feature in non-production
      systems so we can collect early feedback about performance.

      .. __: https://docs.openstack.org/keystone/latest/admin/unified-limits.html

    - Keystone's policy concepts of system vs. project scope and roles has been
      implemented in Nova and `defaults roles and scopes have been defined`__,
      while legacy policies continue to be enabled by default. Operators are
      encouraged to familiarize with the new policies and `enable them
      in advance`__ before Nova switches from the legacy roles in a later
      release.

      .. __: https://docs.openstack.org/nova/latest/configuration/policy-concepts.html#nova-supported-scope-roles
      .. __: https://docs.openstack.org/nova/latest/configuration/policy-concepts.html#migration-plan


    - Support is added for network backends that leverage SmartNICs to
      `offload the control plane from the host server`__. Accordingly, Neutron
      needs to be `configured`__ in order to enable it correctly.
      Increased security is enabled by removing the control plane from the
      host server and overhead is reduced by leveraging the cpu and ram
      resources on modern SmartNIC DPUs.

      .. __: https://docs.openstack.org/nova/latest/admin/networking.html#sr-iov
      .. __: https://docs.openstack.org/neutron/latest/admin/ovn/smartnic_dpu


    - Experimental support for `emulated architecture is now implemented`__.
      AArch64, PPC64LE, MIPs, and s390x guest architectures are
      available independent of the host architecture. This is strictly not
      intended for production use for various reasons, including no security
      guarantees.

      .. __: https://docs.openstack.org/nova/latest/admin/hw-emulation-architecture.html