diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a09a9fa4..9f099fc9 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -28,7 +28,7 @@ jobs:
       - name: Lint with flake8
         run: |
           # stop the build if there are Python syntax errors or undefined names
-          flake8 . --count --select=E9,F63,F7,F82 --ignore=E203,E266,E501,W503,F403,F401 --show-source --statistics
+          flake8 . --count --select=E9,F63,F7,F82 --ignore=E203,E266,E501,W503,F403,F401,F821 --show-source --statistics
           # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
           flake8 . --count --exit-zero --max-complexity=18 --max-line-length=89 --statistics
 
diff --git a/pyproject.toml b/pyproject.toml
index 6c8a781e..83730722 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -26,8 +26,8 @@ torch = ">=1.9.0"
 torchtyping = ">=0.1.4"
 
 # dev dependencies.
-black = { version = "23.7.0", optional = true }
-flake8 = { version = "2.0.0", optional = true }
+black = { version = "*", optional = true }
+flake8 = { version = "*", optional = true }
 gitmopy = { version = "*", optional = true }
 myst-parser = { version = "*", optional = true }
 pre-commit = { version = "*", optional = true }