---
upgrade:
  - |
    `SESSION_ENGINE` has been changed to memcached by default. So that
    horizon do not require it's own database for storing session
    information anymore. `horizon_galera_*` variables has no effect now.
features:
  - |
    Added variables `horizon_session_engine` and `horizon_session_caches`
    which can be used to configure horizon session engine and a backend
    for it.