Downgrade deprecation warnings to use console.warn instead of console.error. (@flarnie in #9753)
Add a deprecation warning for React.createClass. Points users to create-react-class instead. (@flarnie in #9771)
Add deprecation warnings and separate module for React.DOM factory helpers. (@nhunzaker in #8356)
Warn for deprecation of React.createMixin helper, which was never used. (@aweary in #8853)

Add support for CSS variables in style attribute. (@aweary in #9302)
Add support for CSS Grid style properties. (@ericsakmar in #9185)
Fix bug where inputs mutated value on type conversion. (@nhunzaker in #9806)
Fix issues with onChange not firing properly for some inputs. (@jquense in #8575)
Fix bug where controlled number input mistakenly allowed period. (@nhunzaker in #9584)
Fix bug where performance entries were being cleared. (@chrisui in #9451)

Fix AMD support for addons depending on react. (@flarnie in #9919)
Fix isMounted() to return true in componentWillUnmount. (@mridgway in #9638)
Fix react-addons-update to not depend on native Object.assign. (@gaearon in #9937)
Remove broken Google Closure Compiler annotation from create-react-class. (@gaearon in #9933)
Remove unnecessary dependency from react-linked-input. (@gaearon in #9766)
Point react-addons-(css-)transition-group to the new package. (@gaearon in #9937)