diff --git a/poetry.lock b/poetry.lock
index de6af8ae36c051e4009b7f8871388d12e585857f..d6e72d49992c2f09cada25a1a66a7679861c60e5 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -77,26 +77,27 @@ tests = ["pytest (>=4.6)", "pytest-flake8", "pytest-cov", "PyHamcrest (>=2.0.2)"
 
 [[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"
 dataclasses = {version = ">=0.6", markers = "python_version < \"3.7\""}
 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"
@@ -627,7 +628,7 @@ testing = ["pytest (>=4.6)", "pytest-checkdocs (>=1.2.3)", "pytest-flake8", "pyt
 [metadata]
 lock-version = "1.1"
 python-versions = "^3.6.8"
-content-hash = "7c299b0c64637726934acf19f0bdf24a25e04e2d56ff5bc6ff4f043144bf61fd"
+content-hash = "904d9578098b972ce50320cb402e289f962e656c205c86930f9fc3bbfaa3a83e"
 
 [metadata.files]
 aiohttp = [
@@ -694,7 +695,8 @@ base58 = [
     {file = "base58-2.1.0.tar.gz", hash = "sha256:171a547b4a3c61e1ae3807224a6f7aec75e364c4395e7562649d7335768001a2"},
 ]
 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 611ec5e00ef5da38f91c8dcdcc4a29bd3d524c89..7296aa89b8989a751c59d67cd205b699a5b749b2 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -20,7 +20,7 @@ texttable = "^1.6.3"
 pendulum = "^2.1.2"
 
 [tool.poetry.dev-dependencies]
-black = "^20.8b1"
+black = {version = "^21.4b2", allow-prereleases = true}
 pre-commit = "^2.10.1"
 pytest = "^6.0"
 pytest-cov = "^2.7"