DOC: add API changes notes

tacaswell · tacaswell · commit 0f9c6fb89fb9 · 2017-10-22T14:07:39.000-04:00
diff --git a/doc/api/api_changes.rst b/doc/api/api_changes.rst
@@ -10,9 +10,24 @@ out what caused the breakage and how to fix it by updating your code.
 For new features that were added to Matplotlib, please see
 :ref:`whats-new`.
 
+API Changes in 2.1.1
+====================
+
+Default behavior of log scales reverted to clip <= 0 values
+-----------------------------------------------------------
+
+The change it 2.1.0 to mask in logscale by default had more disruptive
+changes than anticipated and has been reverted, however the clipping is now
+done in a way that fixes the issues that motivated changing the default behavior
+to ``'mask'``.
+
+As a side effect of this change, error bars which go negative now work as expected
+on log scales.
+
 API Changes in 2.1.0
 ====================
 
+
 Default behavior of log scales changed to mask <= 0 values
 ----------------------------------------------------------
 
