diff --git a/docs/release_notes/version_0.14_updates.rst b/docs/release_notes/version_0.14_updates.rst
index 445b80e2d..4950a4724 100644
--- a/docs/release_notes/version_0.14_updates.rst
+++ b/docs/release_notes/version_0.14_updates.rst
@@ -44,6 +44,11 @@ When :meth:`~data.core.fieldlist.FieldList.to_xarray` is called with ``split_dim
 See the :ref:`/examples/xarray_engine_split.ipynb` notebook example.
 
 
+Patterns
++++++++++++++++++++++++++++++
+
+The ``allow_missing_keys`` keyword argument was removed from :py:meth:`Patterns.__init__`. When :py:class:`Patterns` was created with ``allow_missing_keys=True`` it allowed passing parameters to :py:meth:`Patterns.substitue` which were not part of the pattern. This behaviour can now be controlled by passing the ``allow_extra=True`` keyword argument to each :py:meth:`Patterns.substitue` call. This is a **breaking change** (:pr:`659`).
+
 New features
 +++++++++++++++++