.. _faq_deprecation: How are configuration deprecations handled? =========================================== As documented in the "Breaking change policy" in :repo:`CONTRIBUTING.md`, features can be marked as deprecated at any point as long as there is a replacement available. Each deprecation is annotated in the API proto itself and explained in detail in the :ref:`Envoy documentation `. For the first 3 months following deprecation, use of deprecated fields will result in a logged warning and incrementing the :ref:`deprecated_feature_use ` counter. After that point, the field will be annotated as fatal-by-default and further use of the field will be treated as invalid configuration unless :ref:`runtime overrides ` are employed to re-enable use.