diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index f88419a..72dc7c8 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -8,7 +8,7 @@ jobs:
     strategy:
       matrix:
         os: [ ubuntu-latest ]
-        python-version: ['3.6', '3.7', '3.8', '3.9', '3.10']
+        python-version: ['3.6.*', '3.7.*', '3.8.*', '3.9.*', '3.10.*']
     steps:
       - uses: actions/checkout@v4
       - name: Install poetry
diff --git a/Makefile b/Makefile
index e4db5c7..49925b9 100644
--- a/Makefile
+++ b/Makefile
@@ -33,12 +33,12 @@ test:
 	pytest
 
 style_check:
-	isort --check-only --recursive shamir_mnemonic/ *.py
+	isort --check-only shamir_mnemonic/ *.py
 	black shamir_mnemonic/ *.py --check
 
 style:
 	black shamir_mnemonic/ *.py
-	isort -y --recursive shamir_mnemonic/ *.py
+	isort shamir_mnemonic/ *.py
 
 
 .PHONY: clean clean-build clean-pyc clean-test test style_check style
diff --git a/pyproject.toml b/pyproject.toml
index 720c811..594bbe6 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -10,15 +10,14 @@ readme = [
 ]
 
 [tool.poetry.dependencies]
-python = ">=3.6"
+python = ">=3.6,<4.0"
 click = ">=7,<9"
 bip32utils = "^0.3.post4"
 pytest = "*"
 
 [tool.poetry.group.dev.dependencies]
-black = "*"
-flake8 = "*"
-isort = "*"
+black = ">=20"
+isort = "^5"
 
 [build-system]
 requires = ["poetry-core"]