v0.12.0

Likely to cause new Flow errors:

• Fixed a bug where declarations from libraries which are exported from one module are not checked properly in the module into which that module is imported (e.g. if A.foo() returns a Promise, and module B requires A and calls A.foo(), the return type of A.foo() was not being checked properly)
• Fixed enforcement of Object and Function type annotation arity, so that Object<K, V> errors
• Restricted valid computed properties, such that only strings and numbers are allowed (notably, disallows null and undefined)

New features:

• Added support for for-of and support for Iterable interface(s)
• Added support for async/await
• Added structural subtyping for interfaces -- anything can be an instance of an interface as long as it looks right
• Added support for type annotations of the form typeof x, where x is the name of an in-scope variable
• Added a new config option suppress_comment, a regexp which matches against comments and causes any Flow error on the next line to be suppressed. For example, suppress_comment=.*\$FlowFixMe.* will cause /* $FlowFixMe */\nvar x : number = "oops"; to not raise an error.
• Added a new config option module.name_mapper, a regexp -> replacement template tuple to be applied to any matching module names before the Flow system resolves the name and looks it up
• Added a --color=always|never|auto CLI option, useful when piping to less -R
• Added a --one-line CLI option which replaces \n with \\n in multiline error messages, useful when piping to grep

Misc:

• Many improvements to library files, especially node and ES6 APIs
• Improved warnings on unsupported class members [PR #461]
• Added support for export default class
• Fixed if (x instanceof Array)
• Fixed the type of x && y when x is an array, object or function
• Fixed the flow get-def command, especially around imported types
• Fixed a bug with == and improved comparison-related error messages
• Fixed file watching for individual files included via .flowconfig [includes]
• Fixed the build ID, so that the server restarts when accessed from a mismatched client version
• Added a new config option log.file which overrides the default log file path

v0.11.0

• We are now syncing Flow's commit history to GitHub. No more huge updating diffs. We'll also filter the changelog to the most important things.
• Big React refactoring to support ES6 React classes
• Do you use any to workaround things that you want to fix later? Well, now you can use $FixMe instead of any and easily grep for these workarounds later.
• We now report parsing errors in non-@flow files that you are require()'ing/import'ing
• Better error messages and better error message positions
• Better error traces, with flow check --traces N, where N is the trace depth
• Basic support for Object.freeze()
• Assorted fixes and updates to the flow libs
• We're trying to be better about commenting the code

v0.10.0

• Support import/export type
• [PR #412] More fs implementation
• Support for static overloads
• Fix order of args matched with overloads
• Allow methods to have properties
• [PR #405] Make interface-defined modules work with CommonJS/ES6Module interop
• Refine mixed
• Fix typeof null === "object" refinement
• [PR #397] Facilitate debug builds
• [PR #401] Improve error message clarity in a few places
• Remove 'everything is a bool' implicit cast
• Fix issues with optional properties during InstanceT ~> ObjT
• Fix abnormals in catch blocks

v0.9.2

• Fix lowercasing issue where "flow Path/To/Root" became "flow path/to/root"
• Fix "My Path/To Flow/flow path/to/root" not autostarting server due to spaces

v0.9.1

• Unbreak the command line for "flow path/to/root" (thanks @samwgoldman for the report!)

v0.9.0

• Add Video-, Audio and TextTrackList (+ dependencies)
• Refine switch cases
• Better Not_found error
• [PR #333] Partial fs module implementation
• Update parser to match esprima-fb
• [PR #370] Dom canvas context
• [PR #393] Symbol should be called statically. Fix #391
• Fix havoc_env to copy the for_type value
• add bash completion
• rewrite all the commands to use CommandSpec
• json_of_t
• [PR #384] Env printer
• [PR #383] Add some build/test artifacts to .gitignore
• [PR #377] Add missing HTMLImageElement properties
• [PR #367] Re-add merged out oneOfType proptype implementation
• Allow users to pin their .flowconfig to a specific version
• colorize test failure diffs
• Object spread fix
• [PR #322] Add type signature for node "url", "querystring" and "path" modules
• command parsing library
• look for package.json in include paths
• clear module errors properly
• add verbose mode

v0.8.0

• [PR #356] Add React.version to lib/react.js
• [PR #331] node http.get() implementation
• Fixes for indexers in object types and objects used as dictionaries
• Flow server speedup
• Support both commas and semicolons in object type patterns
• Fix object assign for unresolved objects
• Add prerr_endlinef
• Fix support for the mixin pattern of specifying super
• Incremental typechecking fix
• Fix up promises interface definition + more tests
• Perf win by loading master_cx once per job
• Support for-in of null and undefined
• Support typeof x === 'boolean'
• Refine true and false literals
• Fix refinement unit test
• Type declarations for Geolocation interface
• [PR #321] Support for React.cloneElement in 0.13
• Refine simple assignments (things like while (x = x.parent) { x.doStuff(); })

v0.7.0

• Initial support for ES6 import/export (with CommonJS interop)
• Updates to CSS/CSSOM interface definitions
• propTypes in React components now dictate the concrete type signature for this.props
• Show errors in type-at-pos output
• Flow now watches include paths specified in .flowconfig for file changes
• Interpret x != undefined and x != null as the same refinement
• Use Object.prototype.hasOwnProperty() calls as a refinement
• Updates to Element and HTMLElement interface definitions

v0.6.0

• Also watch for changes in include paths
• Fix the Function type to be any function
• Add Symbol global name to libs
• Support trailing commas in parser
• Make methods immutable
• Remove tuple array length limit
• [PR #315] Implement more PropTypes
• Update componentWillReceive spec
• Unsuppress library errors

v0.5.0

• Add HTMLAnchorElement
• [PR #295] Add one of proptype
• Update the parser to work with the new esprima-fb & ast-types
• [PR #299] Declare prompt function (fixes #204)
• [PR #303] Add String.prototype.endsWith()
• quick fix for react/es6 notation
• extend scope of type params to following bounds
• reasonless shortcut
• Add React.findDOMNode to lib/react.js
• move command documentation into each command
• fix path in --help usage example
• fix predicate filtering of null and undefined
• [PR #292] Types for React synthetic events
• basic support for bounded polymorphism
• infer falsiness
• node haste module support
• add Abnormal.string