diff --git a/.bumpversion.cfg b/.bumpversion.cfg
index 642ba2fa..9ebbd47d 100644
--- a/.bumpversion.cfg
+++ b/.bumpversion.cfg
@@ -1,5 +1,5 @@
 [bumpversion]
-current_version = 3.12.0
+current_version = 4.0.0
 commit = True
 tag = False
 
diff --git a/doc/conf.py b/doc/conf.py
index 7c9691fa..3d61147b 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -52,7 +52,7 @@
 # built documents.
 #
 # The short X.Y version.
-version = '3.12.0'
+version = '4.0.0'
 # The full version, including alpha/beta/rc tags.
 release = version #+ '.1'
 
diff --git a/doc/history.rst b/doc/history.rst
index aaa89661..6f0db3c6 100644
--- a/doc/history.rst
+++ b/doc/history.rst
@@ -1,6 +1,46 @@
 Release history
 ===============
 
+Version 4.0
+-----------
+
+This version contains breaking changes, but most projects which are already
+using the ``[project]`` table for metadata shouldn't be affected, and can simply
+change the ``flit_core <4`` constraint to ``<5``.
+
+- The ``[tool.flit.metadata]`` table is no longer used for project metadata
+  (:ghpull:`771`). Use the newer :ref:`[project] table <pyproject_toml_project>`
+  instead (or if that is not possible, build with ``flit_core <4``).
+- :ref:`build_cmd` and :ref:`publish_cmd` no longer include files in the sdist
+  based on what is committed in git or Mercurial (:ghpull:`772`). These commands
+  now build packages more like Flit does when called as a backend by e.g.
+  ``python -m build``. Specify :ref:`sdist include & exclude patterns
+  <pyproject_toml_sdist>` instead (Flit can help to generate these), or pass
+  the ``--use-vcs`` option to get the old behaviour back.
+- ``flit_core`` now requires Python 3.8 or above (:ghpull:`738`)
+- The ``--setup-py`` option to generate sdists containing a ``setup.py`` file
+  is no longer available (:ghpull:`776`).
+- Making typing stubs packages with a ``-stubs`` suffix will now work
+  (:ghpull:`742`).
+- The default glob patterns for license files have been extended to include
+  ``NOTICE*`` and ``AUTHORS*`` (:ghpull:`758`).
+- ``license-files`` glob patterns can contain spaces (:ghpull:`797`).
+- Fix a bug where license files could be found twice on Windows (:ghpull:`752`).
+- The new ``Import-Name`` and ``Import-Namespace`` metadata fields (metadata 2.5)
+  are now supported (:ghpull:`774`). In most cases no new input is required,
+  as Flit will create this metadata automatically.
+- Fix creating RECORD files when file names include commas (:ghpull:`744`).
+- The ``--use-vcs`` option now correctly recognises git from inside a git
+  worktree folder (:ghpull:`799`).
+- On Python 3.12 and above, ``flit build`` now uses the 'data' filter when
+  extracting the just-created sdist prior to building a wheel (:ghpull:`775`).
+  This restricts some special features of tar files, but sdists are unlikely
+  to use these features, and they would probably break in other scenarios if
+  you did.
+- The vendorised ``readme_renderer`` package was updated to version 44.0
+  (:ghpull:`760`).
+
+
 Version 3.12
 ------------
 
diff --git a/doc/pyproject_toml.rst b/doc/pyproject_toml.rst
index 3ff40489..d58850bf 100644
--- a/doc/pyproject_toml.rst
+++ b/doc/pyproject_toml.rst
@@ -36,6 +36,7 @@ Version constraints:
 - The older ``[tool.flit.metadata]`` metadata table requires ``flit_core >=2,<4``.
 - The very old ``flit.ini`` file requires ``flit_core <3``.
 - TOML features new in version 1.0 require ``flit_core >=3.4``.
+- ``flit_core`` 3.12 is the last version supporting Python 3.6 & 3.7.
 - ``flit_core`` 3.3 is the last version supporting Python 3.4 & 3.5. Packages
   supporting these Python versions can only use `TOML v0.5
   <https://toml.io/en/v0.5.0>`_.
diff --git a/flit/__init__.py b/flit/__init__.py
index 8e69338e..286ed519 100644
--- a/flit/__init__.py
+++ b/flit/__init__.py
@@ -12,7 +12,7 @@
 from .config import ConfigError
 from .log import enable_colourful_output
 
-__version__ = '3.12.0'
+__version__ = '4.0.0'
 
 log = logging.getLogger(__name__)
 
diff --git a/flit_core/flit_core/__init__.py b/flit_core/flit_core/__init__.py
index d2cb58db..d573d38e 100644
--- a/flit_core/flit_core/__init__.py
+++ b/flit_core/flit_core/__init__.py
@@ -4,4 +4,4 @@
 All the convenient development features live in the main 'flit' package.
 """
 
-__version__ = '3.12.0'
+__version__ = '4.0.0'
diff --git a/pyproject.toml b/pyproject.toml
index 379b0aa7..4c9db835 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,5 +1,5 @@
 [build-system]
-requires = ["flit_core >=3.11,<4"]
+requires = ["flit_core >=3.11,<5"]
 build-backend = "flit_core.buildapi"
 
 [project]
@@ -8,7 +8,7 @@ authors = [
     {name = "Thomas Kluyver", email = "thomas@kluyver.me.uk"},
 ]
 dependencies = [
-    "flit_core >=3.12.0",
+    "flit_core >=4.0.0",
     "requests",
     "docutils",
     "tomli-w",