diff --git a/CHANGELOG.md b/CHANGELOG.md
index fe057134..2150e75e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,11 +1,14 @@
 Sydent 2.4.0 (2021-09-09)
 =========================
+TODO link to docs
+**Action required when upgrading**: server administrators should run [the case-folding migration script](./docs/casefold_migration.md). Sydent does not need to be stopped whilst running this script.
 
 Features
 --------
 
 - Experimental support for [MSC3288](https://github.com/matrix-org/matrix-doc/pull/3288), receiving `room_type` for 3pid invites over the `/store-invite` API and using it in Jinja templates for Space invites. ([\#375](https://github.com/matrix-org/sydent/issues/375))
-- Add support for using Jinja2 in e-mail templates. Contributed by H-Shay. ([\#376](https://github.com/matrix-org/sydent/issues/376))
+- Add support for using Jinja2 in e-mail templates. Contributed by H. Shay. ([\#376](https://github.com/matrix-org/sydent/issues/376))
+- Case-fold email addresses when binding to MXIDs or performing look-ups. Contributed by H. Shay. ([\#374](https://github.com/matrix-org/sydent/issues/374), [\#378](https://github.com/matrix-org/sydent/issues/378), [\#379](https://github.com/matrix-org/sydent/issues/379), [\#386](https://github.com/matrix-org/sydent/issues/386))
 
 
 Bugfixes
@@ -18,10 +21,10 @@ Bugfixes
 Internal Changes
 ----------------
 
-- Add /_trial_temp.lock and /sydent.pid to .gitignore. ([\#284](https://github.com/matrix-org/sydent/issues/284))
-- Update black to 21.6b0. Contributed by H.Shay. ([\#343](https://github.com/matrix-org/sydent/issues/343), [\#369](https://github.com/matrix-org/sydent/issues/369))
-- Configure Flake8 and resolve errors. ([\#344](https://github.com/matrix-org/sydent/issues/344), [\#347](https://github.com/matrix-org/sydent/issues/347))
-- Add github actions for unittests (python 3.6 and 3.9), matrix_is_tester tests (python 3.6 and 3.9), towncrier checks and black and flake8 codestyle checks. ([\#346](https://github.com/matrix-org/sydent/issues/346), [\#348](https://github.com/matrix-org/sydent/issues/348))
+- Add /_trial_temp.lock and /sydent.pid to .gitignore. ([\#384](https://github.com/matrix-org/sydent/issues/384))
+- Reformat code using Black. Contributed by H. Shay. ([\#344](https://github.com/matrix-org/sydent/issues/344), [\#369](https://github.com/matrix-org/sydent/issues/369))
+- Configure Flake8 and resolve errors. ([\#345](https://github.com/matrix-org/sydent/issues/345), [\#347](https://github.com/matrix-org/sydent/issues/347))
+- Add GitHub Actions for unit tests (Python 3.6 and 3.9), matrix_is_tester tests (Python 3.6 and 3.9), towncrier checks and black and flake8 codestyle checks. ([\#346](https://github.com/matrix-org/sydent/issues/346), [\#348](https://github.com/matrix-org/sydent/issues/348))
 - Remove support for Python < 3.6. ([\#349](https://github.com/matrix-org/sydent/issues/349), [\#356](https://github.com/matrix-org/sydent/issues/356))
 - Bump minimum supported version of Twisted to 18.4.0 and stop calling deprecated APIs. ([\#350](https://github.com/matrix-org/sydent/issues/350))
 - Replace deprecated `logging.warn()` method with `logging.warning()`. ([\#351](https://github.com/matrix-org/sydent/issues/351))
@@ -30,7 +33,6 @@ Internal Changes
 - Add type hints and validate with mypy. ([\#355](https://github.com/matrix-org/sydent/issues/355), [\#357](https://github.com/matrix-org/sydent/issues/357), [\#358](https://github.com/matrix-org/sydent/issues/358), [\#360](https://github.com/matrix-org/sydent/issues/360), [\#361](https://github.com/matrix-org/sydent/issues/361), [\#367](https://github.com/matrix-org/sydent/issues/367), [\#371](https://github.com/matrix-org/sydent/issues/371))
 - Convert `inlineCallbacks` to async/await. ([\#364](https://github.com/matrix-org/sydent/issues/364), [\#365](https://github.com/matrix-org/sydent/issues/365), [\#368](https://github.com/matrix-org/sydent/issues/368), [\#372](https://github.com/matrix-org/sydent/issues/372), [\#373](https://github.com/matrix-org/sydent/issues/373))
 - Use `mock` module from the standard library. ([\#370](https://github.com/matrix-org/sydent/issues/370))
-- Case-fold email addresses when binding to MXIDs or performing look-ups. Contributed by H. Shay. ([\#374](https://github.com/matrix-org/sydent/issues/374), [\#378](https://github.com/matrix-org/sydent/issues/378), [\#379](https://github.com/matrix-org/sydent/issues/379), [\#386](https://github.com/matrix-org/sydent/issues/386))
 - Fix email templates to be valid python format strings. ([\#377](https://github.com/matrix-org/sydent/issues/377))