diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 70ae6925..f93e9b83 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -1,3 +1,8 @@
+6.3.1
+=====
+
+* fix #625: restore tomli in install_requires after the regression changes in took it out
+  and some users never added it even tho they have pyproject.toml files
 
 6.3.0
 =======
diff --git a/setup.cfg b/setup.cfg
index df9ef8d1..3fe4541d 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -29,6 +29,7 @@ packages = find:
 install_requires =
     packaging>=20.0
     setuptools
+    tomli>=1.0.0 # keep in sync
 python_requires = >=3.6
 package_dir =
     =src