diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 3e2239c..bf6743d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -43,6 +43,20 @@ jobs:
           pip install virtualenv nox
           nox -f noxfile.py -s type_check
 
+  compatibility-3-13:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install system dependencies
+        run: sudo apt-get update && sudo apt-get install -y libjpeg-dev
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.13'
+      - run: |
+          pip install virtualenv nox
+          nox -f noxfile.py -s compatibility
+
   compatibility-3-12:
     runs-on: ubuntu-latest
     steps:
diff --git a/build_golden_images.py b/build_golden_images.py
index 7ed730d..52ca9c3 100644
--- a/build_golden_images.py
+++ b/build_golden_images.py
@@ -18,7 +18,7 @@
 import json
 import os
 import os.path
-import pkg_resources
+import importlib.resources
 
 import pybadges
 from tests import image_server
@@ -46,17 +46,22 @@ def main():
     parser = argparse.ArgumentParser(
         description='generate a github-style badge given some text and colors')
 
-    parser.add_argument(
-        '--source-path',
-        default=pkg_resources.resource_filename(__name__,
-                                                'tests/test-badges.json'),
-        help='the text to show on the left-hand-side of the badge')
+    with importlib.resources.as_file(
+            importlib.resources.files('tests') /
+            'test-badges.json') as test_badges_path:
+        parser.add_argument(
+            '--source-path',
+            default=str(test_badges_path),
+            help='the text to show on the left-hand-side of the badge')
+
+    with importlib.resources.as_file(
+            importlib.resources.files('tests') /
+            'golden-images') as golden_images_path:
+        parser.add_argument(
+            '--destination-dir',
+            default=str(golden_images_path),
+            help='the text to show on the left-hand-side of the badge')
 
-    parser.add_argument(
-        '--destination-dir',
-        default=pkg_resources.resource_filename(__name__,
-                                                'tests/golden-images'),
-        help='the text to show on the left-hand-side of the badge')
     args = parser.parse_args()
     generate_images(args.source_path, args.destination_dir)
 
diff --git a/noxfile.py b/noxfile.py
index fedd5f4..930ad3d 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -45,7 +45,7 @@ def unit(session):
     'install',
     [
         'Jinja2==3.0.0',
-        'Pillow==8.3.2',  # Oldest version that supports Python 3.7 to 3.10.
+        'Pillow>=11.2.1,<12.0.0',
         'requests>=2.25.0,<3.0.0',
         'urllib3>=1.25.0,<2.0.0',  # urllib3 2.0.0+ requires Python 3.8+
         'xmldiff==2.4'
diff --git a/pybadges/__init__.py b/pybadges/__init__.py
index 0bc6bee..87a3eff 100644
--- a/pybadges/__init__.py
+++ b/pybadges/__init__.py
@@ -30,12 +30,12 @@
 """
 
 import base64
-import imghdr
 import mimetypes
 from typing import Optional
 import urllib.parse
 from xml.dom import minidom
 
+import filetype
 import jinja2
 import requests
 
@@ -102,7 +102,8 @@ def _embed_image(url: str) -> str:
     else:
         with open(url, 'rb') as f:
             image_data = f.read()
-        image_type = imghdr.what(None, image_data)
+        kind = filetype.guess(image_data)
+        image_type = kind.extension if kind is not None else None
         if not image_type:
             mime_type, _ = mimetypes.guess_type(url, strict=False)
             if not mime_type:
diff --git a/pybadges/precalculated_text_measurer.py b/pybadges/precalculated_text_measurer.py
index 6e769af..5374f99 100644
--- a/pybadges/precalculated_text_measurer.py
+++ b/pybadges/precalculated_text_measurer.py
@@ -18,7 +18,8 @@
 
 import io
 import json
-import pkg_resources
+import importlib.resources
+import lzma
 from typing import cast, Mapping, TextIO, Type
 
 from pybadges import text_measurer
@@ -74,19 +75,23 @@ def default(cls) -> 'PrecalculatedTextMeasurer':
         if cls._default_cache is not None:
             return cls._default_cache
 
-        if pkg_resources.resource_exists(__name__, 'default-widths.json.xz'):
-            import lzma
-            with pkg_resources.resource_stream(__name__,
-                                               'default-widths.json.xz') as f:
-                with lzma.open(f, "rt") as g:
-                    cls._default_cache = PrecalculatedTextMeasurer.from_json(
-                        cast(TextIO, g))
+        try:
+            if importlib.resources.is_resource(__package__,
+                                               'default-widths.json.xz'):
+                with importlib.resources.open_binary(
+                        __package__, 'default-widths.json.xz') as f:
+                    with lzma.open(f, "rt") as g:
+                        cls._default_cache = PrecalculatedTextMeasurer.from_json(
+                            cast(TextIO, g))
+                        return cls._default_cache
+            elif importlib.resources.is_resource(__package__,
+                                                 'default-widths.json'):
+                with importlib.resources.open_text(__package__,
+                                                   'default-widths.json',
+                                                   encoding='utf-8') as f:
+                    cls._default_cache = PrecalculatedTextMeasurer.from_json(f)
                     return cls._default_cache
-        elif pkg_resources.resource_exists(__name__, 'default-widths.json'):
-            with pkg_resources.resource_stream(__name__,
-                                               'default-widths.json') as f:
-                cls._default_cache = PrecalculatedTextMeasurer.from_json(
-                    io.TextIOWrapper(f, encoding='utf-8'))
-                return cls._default_cache
-        else:
-            raise ValueError('could not load default-widths.json')
+            else:
+                raise ValueError('could not load default-widths.json')
+        except Exception as e:
+            raise ValueError(f'Error loading default-widths.json: {e}')
diff --git a/setup.py b/setup.py
index 88559b2..61ee93f 100644
--- a/setup.py
+++ b/setup.py
@@ -47,14 +47,11 @@ def replace_relative_with_absolute(match):
         'Intended Audience :: Developers',
         'Intended Audience :: Developers',
         'License :: OSI Approved :: Apache Software License',
-        'Programming Language :: Python',
-        'Programming Language :: Python :: 3',
-        'Programming Language :: Python :: 3.7',
-        'Programming Language :: Python :: 3.8',
         'Programming Language :: Python :: 3.9',
         'Programming Language :: Python :: 3.10',
         'Programming Language :: Python :: 3.11',
         'Programming Language :: Python :: 3.12',
+        'Programming Language :: Python :: 3.13',
         'Operating System :: OS Independent',
     ],
     description='A library and command-line tool for generating Github-style ' +
@@ -67,8 +64,10 @@ def replace_relative_with_absolute(match):
     },
     long_description=get_long_description(),
     long_description_content_type='text/markdown',
-    python_requires='>=3.4',
-    install_requires=['Jinja2>=3,<4', 'requests>=2.22.0,<3'],
+    python_requires='>=3.9',
+    install_requires=[
+        'Jinja2>=3,<4', 'requests>=2.22.0,<3', 'filetype>=1.2.0,<2.0.0'
+    ],
     extras_require={
         'pil-measurement': ['Pillow>=6,<10'],
         'dev': [