Change the deprecation policy around classifiers

Author: befeleme

peps/pep-0639.rst

@@ -451,22 +451,18 @@ in the ``Classifier`` :term:`Core Metadata field`
 (`described in the Core Metadata specification <coremetadataclassifiers_>`__)
 is deprecated and replaced by the more precise ``License-Expression`` field.
 
-If the ``License-Expression`` field is present, build tools SHOULD and
-publishing tools MUST raise an error if one or more license classifiers
+If the ``License-Expression`` field is present, build tools MAY raise an error
+if one or more license classifiers
 is included in a ``Classifier`` field, and MUST NOT add
 such classifiers themselves.
 
-Otherwise, if this field contains a license classifier, build tools MAY
-and publishing tools SHOULD issue a warning informing users such classifiers
+Otherwise, if this field contains a license classifier,
+tools MAY issue a warning informing users such classifiers
 are deprecated, and recommending ``License-Expression`` instead.
 For compatibility with existing publishing and installation processes,
 the presence of license classifiers SHOULD NOT raise an error unless
 ``License-Expression`` is also provided.
 
-For all newly-uploaded distributions that include a
-``License-Expression`` field, the `Python Package Index (PyPI) <pypi_>`__ MUST
-reject any that also specify any license classifiers.
-
 New license classifiers MUST NOT be `added to PyPI <classifiersrepo_>`__;
 users needing them SHOULD use the ``License-Expression`` field instead.
 License classifiers may be removed from a new version of the specification