diff --git a/.github/workflows/publish-docs.yml b/.github/workflows/publish-docs.yml
index ee363fa..8659823 100644
--- a/.github/workflows/publish-docs.yml
+++ b/.github/workflows/publish-docs.yml
@@ -21,7 +21,7 @@ jobs:
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v2
         with:
-          python-version: "3.9"
+          python-version: "3.10"
 
       - name: Install Dependencies
         run: |
diff --git a/.github/workflows/publish-pypi.yml b/.github/workflows/publish-pypi.yml
index 15ba9b5..1785c63 100644
--- a/.github/workflows/publish-pypi.yml
+++ b/.github/workflows/publish-pypi.yml
@@ -16,7 +16,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v3
         with:
-          python-version: "3.9"
+          python-version: "3.10"
 
       - name: Install dependencies
         run: python3 -m pip install --upgrade build
@@ -44,7 +44,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v3
         with:
-          python-version: "3.9"
+          python-version: "3.10"
 
       - name: Install twine
         run: python3 -m pip install --upgrade twine
@@ -75,7 +75,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v3
         with:
-          python-version: "3.9"
+          python-version: "3.10"
 
       - name: Install twine
         run: python3 -m pip install --upgrade twine
diff --git a/formulae/utils.py b/formulae/utils.py
index 5c10f0e..2feccc1 100644
--- a/formulae/utils.py
+++ b/formulae/utils.py
@@ -3,6 +3,8 @@
 import numpy as np
 import pandas as pd
 
+from packaging.version import Version
+
 
 def listify(obj):
     """Wrap all non-list or tuple objects in a list.
@@ -44,7 +46,7 @@ def get_interaction_matrix(x, y):
 def is_categorical_dtype(arr_or_dtype):
     """Check whether an array-like or dtype is of the pandas Categorical dtype."""
     # https://pandas.pydata.org/docs/whatsnew/v2.1.0.html#other-deprecations
-    if pd.__version__ < "2.1.0":
+    if Version(pd.__version__) < Version("2.1.0"):
         return pd.api.types.is_categorical_dtype(arr_or_dtype)
     else:
         if hasattr(arr_or_dtype, "dtype"):  # it's an array
diff --git a/pyproject.toml b/pyproject.toml
index 1392982..4778ffe 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -7,7 +7,7 @@ requires = ["setuptools>=61.0", "setuptools_scm>=8"]
 [project]
 name = "formulae"
 description = "Formulas for mixed-effects models in Python"
-requires-python = ">=3.7"
+requires-python = ">=3.8"
 readme = {file = "README.md", content-type = "text/markdown"}
 license = {file = "LICENSE"}
 dynamic = ["version"]
@@ -15,6 +15,7 @@ maintainers = [{ name = "Tomás Capretto", email = "tomicapretto@gmail.com" }]
 
 dependencies = [
     "numpy>=1.16",
+    "packaging",
     "pandas>=1.0.0",
     "scipy>=1.5.4"
 ]