Merge pull request pypa#1787 from di/update-dynamic-to-include-deprecated-fields

Add definition of deprecated metadata fields

Author: webknjaz

source/specifications/core-metadata.rst

@@ -797,6 +797,11 @@ Examples::
 Deprecated Fields
 =================
 
+Deprecated fields should be avoided, but they are valid metadata fields. They
+may be removed in future versions of the core metadata standard (at which point
+they will only be valid in files that specify a metadata version prior to the
+removal). Tools SHOULD warn users when deprecated fields are used.
+
 .. _home-page-optional:
 .. _core-metadata-home-page: