CHANGES:

- Don't select all local implementations in `dune utop`. Instead, let the
  default implementation selection do its job. (ocaml/dune#2327, fixes ocaml/dune#2323, @TheLortex,
  review by @rgrinberg)

- Check that selected implementations (either by variants or default
  implementations) are indeed implementations. (ocaml/dune#2328, @TheLortex, review by
  @rgrinberg)

- Don't reserve the `Ppx` toplevel module name for ppx rewriters (ocaml/dune#2242, @diml)

- Redesign of the library variant feature according to the ocaml/dune#2134 proposal. The
  set of variants is now computed when the virtual library is installed.
  Introducing a new `external_variant` stanza. (ocaml/dune#2169, fixes ocaml/dune#2134, @TheLortex,
  review by @diml)

- Add proper line directives when copying `.cc` and `.cxx` sources (ocaml/dune#2275,
  @rgrinberg)

- Fix error message for missing C++ sources. The `.cc` extension was always
  ignored before. (ocaml/dune#2275, @rgrinberg)

- Add `$ dune init project` subcommand to create project boilerplate according
  to a common template. (ocaml/dune#2185, fixes ocaml/dune#159, @shonfeder)

- Allow to run inline tests in javascript with nodejs (ocaml/dune#2266, @hhugo)

- Build `ppx.exe` as compiling host binary. (ocaml/dune#2286, fixes ocaml/dune#2252, @toots, review
  by @rgrinberg and @diml)

- Add a `cinaps` extension and stanza for better integration with the
  [cinaps tool](https://github.com/janestreet/cinaps) tool (ocaml/dune#2269,
  @diml)

- Allow to embed build info in executables such as version and list
  and version of statically linked libraries (ocaml/dune#2224, @diml)

- Set version in `META` and `dune-package` files to the one read from
  the vcs when no other version is available (ocaml/dune#2224, @diml)

- Add a variable `%{target}` to be used in situations where the context
  requires at most one word, so `%{targets}` can be confusing; stdout
  redirections and "-o" arguments of various tools are the main use
  case; also, introduce a separate field `target` that must be used
  instead of `targets` in those situations.  (ocaml/dune#2341, @aalekseyev)

- Fix dependency graph of wrapped_compat modules. Previously, the dependency on
  the user written entry module was omitted. (ocaml/dune#2305, @rgrinberg)

- Allow to promote executables built with an `executable` stanza
  (ocaml/dune#2379, @diml)

- When instantiating an implementation with a variant, make sure it matches
  virtual library's list of known implementations. (ocaml/dune#2361, fixes ocaml/dune#2322,
  @TheLortex, review by @rgrinberg)

- Add a variable `%{ignoring_promoted_rules}` that is `true` when
  `--ingore-promoted-rules` is passed on the command line and false
  otherwise (ocaml/dune#2382, @diml)

- Fix a bug in `future_syntax` where the characters `@` and `&` were
  not distinguished in the names of binding operators (`let@` was the
  same as `let&`) (ocaml/dune#2376, @aalekseyev, @diml)

- Workspaces with non unique project names are now supported. (ocaml/dune#2377, fix ocaml/dune#2325,
  @rgrinberg)

- Improve opam generation to include the `dune` dependncies with the minimum
  constraint set based on the dune language version specified in the
  `dune-project` file. (2383, @avsm)

- The order of fields in the generated opam file now follows order preferred in
  opam-lib. (@avsm, ocaml/dune#2380)

- Fix coloring of error messages from the compiler (@diml, ocaml/dune#2384)

- Add warning `66` to default set of warnings starting for dune projects with
  language verison >= `1.11` (@rgrinberg, @diml, fixes ocaml/dune#2299)

- Add (dialect ...) stanza
  (@nojb, ocaml/dune#2404)

- Add a `--context` argument to `dune install/uninstall` (@diml, ocaml/dune#2412)

- Do not warn about merlin files pre 1.9. This warning can only be disabled in
  1.9 (ocaml/dune#2421, fixes ocaml/dune#2399, @emillon)

CHANGES:

- Don't select all local implementations in `dune utop`. Instead, let the
  default implementation selection do its job. (ocaml/dune#2327, fixes ocaml/dune#2323, @TheLortex,
  review by @rgrinberg)

- Check that selected implementations (either by variants or default
  implementations) are indeed implementations. (ocaml/dune#2328, @TheLortex, review by
  @rgrinberg)

- Don't reserve the `Ppx` toplevel module name for ppx rewriters (ocaml/dune#2242, @diml)

- Redesign of the library variant feature according to the ocaml/dune#2134 proposal. The
  set of variants is now computed when the virtual library is installed.
  Introducing a new `external_variant` stanza. (ocaml/dune#2169, fixes ocaml/dune#2134, @TheLortex,
  review by @diml)

- Add proper line directives when copying `.cc` and `.cxx` sources (ocaml/dune#2275,
  @rgrinberg)

- Fix error message for missing C++ sources. The `.cc` extension was always
  ignored before. (ocaml/dune#2275, @rgrinberg)

- Add `$ dune init project` subcommand to create project boilerplate according
  to a common template. (ocaml/dune#2185, fixes ocaml/dune#159, @shonfeder)

- Allow to run inline tests in javascript with nodejs (ocaml/dune#2266, @hhugo)

- Build `ppx.exe` as compiling host binary. (ocaml/dune#2286, fixes ocaml/dune#2252, @toots, review
  by @rgrinberg and @diml)

- Add a `cinaps` extension and stanza for better integration with the
  [cinaps tool](https://github.com/janestreet/cinaps) tool (ocaml/dune#2269,
  @diml)

- Allow to embed build info in executables such as version and list
  and version of statically linked libraries (ocaml/dune#2224, @diml)

- Set version in `META` and `dune-package` files to the one read from
  the vcs when no other version is available (ocaml/dune#2224, @diml)

- Add a variable `%{target}` to be used in situations where the context
  requires at most one word, so `%{targets}` can be confusing; stdout
  redirections and "-o" arguments of various tools are the main use
  case; also, introduce a separate field `target` that must be used
  instead of `targets` in those situations.  (ocaml/dune#2341, @aalekseyev)

- Fix dependency graph of wrapped_compat modules. Previously, the dependency on
  the user written entry module was omitted. (ocaml/dune#2305, @rgrinberg)

- Allow to promote executables built with an `executable` stanza
  (ocaml/dune#2379, @diml)

- When instantiating an implementation with a variant, make sure it matches
  virtual library's list of known implementations. (ocaml/dune#2361, fixes ocaml/dune#2322,
  @TheLortex, review by @rgrinberg)

- Add a variable `%{ignoring_promoted_rules}` that is `true` when
  `--ingore-promoted-rules` is passed on the command line and false
  otherwise (ocaml/dune#2382, @diml)

- Fix a bug in `future_syntax` where the characters `@` and `&` were
  not distinguished in the names of binding operators (`let@` was the
  same as `let&`) (ocaml/dune#2376, @aalekseyev, @diml)

- Workspaces with non unique project names are now supported. (ocaml/dune#2377, fix ocaml/dune#2325,
  @rgrinberg)

- Improve opam generation to include the `dune` dependncies with the minimum
  constraint set based on the dune language version specified in the
  `dune-project` file. (2383, @avsm)

- The order of fields in the generated opam file now follows order preferred in
  opam-lib. (@avsm, ocaml/dune#2380)

- Fix coloring of error messages from the compiler (@diml, ocaml/dune#2384)

- Add warning `66` to default set of warnings starting for dune projects with
  language verison >= `1.11` (@rgrinberg, @diml, fixes ocaml/dune#2299)

- Add (dialect ...) stanza
  (@nojb, ocaml/dune#2404)

- Add a `--context` argument to `dune install/uninstall` (@diml, ocaml/dune#2412)

- Do not warn about merlin files pre 1.9. This warning can only be disabled in
  1.9 (ocaml/dune#2421, fixes ocaml/dune#2399, @emillon)

- Add a new `inline_tests` field in the env stanza to control inline_tests
  framework with a variable (ocaml/dune#2313, @mlasson, original idea by @diml, review
  by @rgrinberg).

- New binary kind `js` for executables in order to explicitly enable Javascript
  targets, and a switch `(explicit_js_mode)` to require this mode in order to
  declare JS targets corresponding to executables. (ocaml/dune#1941, @nojb)