also be a wheel 1.1 format update after this PEP is approved that
mandates provision of 2.0+ metadata.
-Other tools involved in Python distribution may also use this format.
+Note that these metadata files SHOULD NOT be processed if the version of the
+containing location is too low to indicate that they are valid. Specifically,
+unversioned ``sdist`` archives, unversioned installation database directories
+and version 1.0 of the ``wheel`` specification do not cover ``pydist.json``
+Other tools involved in Python distribution MAY also use this format.
As JSON files are generally awkward to edit by hand, it is RECOMMENDED
that these metadata files be generated by build tools based on other