Released v16.8

* Fix markers that utilize ``in`` so that they render correctly.
* Fix an erroneous test on Python RC releases.

Released v16.7

* Add support for the deprecated ``python_implementation`` marker which was
  an undocumented setuptools marker in addition to the newer markers.

Released v16.6

* Add support for the deprecated, PEP 345 environment markers in addition to the
  newer markers.

Released v16.5

* Fix a regression in parsing requirements with whitespaces between the comma
  separators.

Released v16.4

* Fix a regression in parsing requirements like ``foo (==4)``.

Released v16.3

* Fix a bug where ``packaging.requirements:Requirement`` was overly strict when
  matching legacy requirements.

Released v16.2

* Add a function that implements the name canonicalization from PEP 503.

Released v16.1

* Implement requirement specifiers from PEP 508.

Released v16.0

* Relicense so that packaging is available under *either* the Apache License,
  Version 2.0 or a 2 Clause BSD license.
* Support installation of packaging when only distutils is available.
* Fix ``==`` comparison when there is a prefix and a local version in play.
  (:issue:`41`).
* Implement environment markers from PEP 508.

Released v15.3

* Normalize post-release spellings for rev/r prefixes. :issue:`35`