diff --git a/poetry.lock b/poetry.lock
index 6d4f867..4e07f59 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -70,25 +70,26 @@ tests_no_zope = ["coverage[toml] (>=5.0.2)", "hypothesis", "pympler", "pytest (>
 
 [[package]]
 name = "black"
-version = "20.8b1"
+version = "21.4b2"
 description = "The uncompromising code formatter."
 category = "dev"
 optional = false
-python-versions = ">=3.6"
+python-versions = ">=3.6.2"
 
 [package.dependencies]
 appdirs = "*"
 click = ">=7.1.2"
 mypy-extensions = ">=0.4.3"
-pathspec = ">=0.6,<1"
+pathspec = ">=0.8.1,<1"
 regex = ">=2020.1.8"
 toml = ">=0.10.1"
-typed-ast = ">=1.4.0"
-typing-extensions = ">=3.7.4"
+typed-ast = {version = ">=1.4.2", markers = "python_version < \"3.8\""}
+typing-extensions = {version = ">=3.7.4", markers = "python_version < \"3.8\""}
 
 [package.extras]
 colorama = ["colorama (>=0.4.3)"]
 d = ["aiohttp (>=3.3.2)", "aiohttp-cors"]
+python2 = ["typed-ast (>=1.4.2)"]
 
 [[package]]
 name = "cfgv"
@@ -513,7 +514,7 @@ testing = ["pytest (>=3.5,!=3.7.3)", "pytest-checkdocs (>=1.2.3)", "pytest-flake
 [metadata]
 lock-version = "1.1"
 python-versions = ">=3.7,<4.0"
-content-hash = "a1069dca263021153f14970f95842c48695ae694122a92ecf9c8117266a75871"
+content-hash = "083c0a4edcdd5c1376aec30fbb3b00d5d87acfedbe7623f42b71a4d85cf82bb7"
 
 [metadata.files]
 aiohttp = [
@@ -576,7 +577,8 @@ attrs = [
     {file = "attrs-20.3.0.tar.gz", hash = "sha256:832aa3cde19744e49938b91fea06d69ecb9e649c93ba974535d08ad92164f700"},
 ]
 black = [
-    {file = "black-20.8b1.tar.gz", hash = "sha256:1c02557aa099101b9d21496f8a914e9ed2222ef70336404eeeac8edba836fbea"},
+    {file = "black-21.4b2-py3-none-any.whl", hash = "sha256:bff7067d8bc25eb21dcfdbc8c72f2baafd9ec6de4663241a52fb904b304d391f"},
+    {file = "black-21.4b2.tar.gz", hash = "sha256:fc9bcf3b482b05c1f35f6a882c079dc01b9c7795827532f4cc43c0ec88067bbc"},
 ]
 cfgv = [
     {file = "cfgv-3.2.0-py2.py3-none-any.whl", hash = "sha256:32e43d604bbe7896fe7c248a9c2276447dbef840feb28fe20494f62af110211d"},
diff --git a/pyproject.toml b/pyproject.toml
index a8c41ee..0a4b805 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -24,7 +24,7 @@ pyhumps = "^1.6.1"
 [tool.poetry.dev-dependencies]
 pytest = "^6.2"
 pre-commit = "^2.11.1"
-black = "^20.8b1"
+black = "^21.4b2"
 pylint = "^2.8.2"
 isort = "^5.8.0"
 mypy = "^0.812"