diff --git a/black.toml b/black.toml
index abdef9fa0..e1a6cfaa5 100644
--- a/black.toml
+++ b/black.toml
@@ -1,5 +1,5 @@
 [tool.black]
-required-version = "21.6b0"
+required-version = "21.9b0"
 line-length = "88"
 skip-string-normalization = true
 target-version = ['py37']
diff --git a/docs/developers.rst b/docs/developers.rst
index fed805056..27dcb1ffb 100644
--- a/docs/developers.rst
+++ b/docs/developers.rst
@@ -13,7 +13,7 @@ Please be as Pythonic as possible (:pep:`8`).
 
 Code should be formatted using `black <https://github.com/psf/black>`_.
 While not yet mandatory, it will be required in the future  (6.0.0+).1
-Use Black v21.6b1, with the black.toml config file provided.
+Use Black v21.9b0, with the black.toml config file provided.
 
 Code should also pass `flake8 <https://github.com/psf/black>`_ linting
 and `mypy <http://mypy-lang.org/>`_ type checking.
diff --git a/requirements.dev.txt b/requirements.dev.txt
index fda1b49ec..27181725a 100644
--- a/requirements.dev.txt
+++ b/requirements.dev.txt
@@ -6,7 +6,7 @@ coverage
 flake8
 doctest-ignore-unicode==0.1.2
 berkeleydb
-black==21.6b0
+black==21.9b0
 flake8-black
 mypy
 types-setuptools
diff --git a/setup.py b/setup.py
index 475242f9b..fc36718f6 100644
--- a/setup.py
+++ b/setup.py
@@ -13,7 +13,7 @@
     "nose==1.3.7",
     "nose-timer",
     "coverage",
-    "black==21.6b0",
+    "black==21.9b0",
     "flake8",
     "doctest-ignore-unicode==0.1.2",
 ]