v2.0.2

• Extract trbl value reducing into a separate module.
• Refactor core longhand optimiser to not rely on trbl cache.
• Adds support for ch units; previously they were removed.
• Fixes parsing of some selector hacks.
• Fixes an issue where embedded base 64 data was being converted as if it were
  a URL.

v2.0.1

• Add postcss-plugin keyword to package.json.
• Wraps all core processors with the PostCSS 4.1 plugin API.

v2.0.0

• Adds removal of outdated vendor prefixes based on browser support.
• Addresses an issue where relative path separators were converted to
  backslashes on Windows.
• cssnano will now detect previous plugins and silently disable them when the
  functionality overlaps. This is to enable faster interoperation with cssnext.
• cssnano now exports as a PostCSS plugin. The simple interface is exposed
  at cssnano.process(css, opts) instead of cssnano(css, opts).
• Improved URL detection when using two or more in the same declaration.
• node 0.10 is no longer officially supported.

v1.4.3

• Fixes incorrect minification of background:none to background:0 0.

v1.4.2

• Fixes an issue with nested URLs inside url() functions.

v1.4.1

• Addresses an issue where whitespace removal after a CSS function would cause
  rendering issues in Internet Explorer.

v1.4.0

• Adds support for removal of unused @keyframes and @counter-style at-rules.
• comments: adds support for user-directed removal of comments, with the
  remove option (thanks to @dmitrykiselyov).
• comments: removeAllButFirst now operates on each CSS tree, rather than the
  first one passed to cssnano.

v1.3.3

• Fixes incorrect minification of border:none to border:0 0.

v1.3.2

• Improved selector minifying logic, leading to better compression of attribute
  selectors.
• Improved comment discarding logic.

v1.3.1

• Fixes crash on undefined decl.before from prior AST.