diff --git a/.github/workflows/build-publish.yml b/.github/workflows/build-publish.yml
index 989d6cf..8893b64 100644
--- a/.github/workflows/build-publish.yml
+++ b/.github/workflows/build-publish.yml
@@ -20,7 +20,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v5
         with:
-          python-version: "3.12"
+          python-version: "3.13"
 
       - name: Install build tools
         run: |
diff --git a/.gitignore b/.gitignore
index f905dc0..26747ab 100644
--- a/.gitignore
+++ b/.gitignore
@@ -12,3 +12,4 @@ pip-selfcheck.json
 
 /.cache/
 dist/
+.idea/
diff --git a/HISTORY.txt b/HISTORY.txt
index 87aea06..58337fb 100644
--- a/HISTORY.txt
+++ b/HISTORY.txt
@@ -1,6 +1,13 @@
 Changelog
 =========
 
+1.4.1.post0+tes
+------------------
+
+- Migrated build system to PEP 517/621.
+- Added pyproject.toml with modern metadata.
+- Declared dynamic readme using setuptools to combine README.rst and HISTORY.txt.
+- Removed legacy setup.py-based build path to avoid deprecation warnings.
 
 1.4.1 (unreleased)
 ------------------
diff --git a/README.rst b/README.rst
index 6ba0d20..5f82ea0 100644
--- a/README.rst
+++ b/README.rst
@@ -2,6 +2,7 @@
 *docxcompose* is a Python library for concatenating/appending Microsoft
 Word (.docx) files.
 
+This fork fixes the DeprecationWarning on pkg_import, and modernizes the build system.
 
 Example usage
 -------------
diff --git a/docxcompose/properties.py b/docxcompose/properties.py
index aa8cd2d..51f2ac0 100644
--- a/docxcompose/properties.py
+++ b/docxcompose/properties.py
@@ -15,7 +15,7 @@
 from lxml.etree import QName
 from six import binary_type
 from six import text_type
-import pkg_resources
+import importlib.resources as importlib_resources
 import re
 
 
@@ -108,8 +108,8 @@ def __init__(self, doc):
             self._element = parse_xml(part.blob)
 
     def _part_template(self):
-        return pkg_resources.resource_string(
-            'docxcompose', 'templates/custom.xml')
+        ref = importlib_resources.files('docxcompose').joinpath('templates/custom.xml')
+        return ref.read_bytes()
 
     def _update_part(self):
         if self.part is None:
diff --git a/pyproject.toml b/pyproject.toml
index 4899954..ae24e9f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,11 +4,17 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "docxcompose_tes"
-authors = [{ name="Telengsol", email="devops+test-pypi@telengsol.com" }]
 description = "Python library for concatenating/appending Microsoft Word (.docx) files."
 readme = "README.rst"
 license = {text = "MIT"}
-dependencies = []
+requires-python = ">=3.13"
+dependencies = [
+    'lxml',
+    'python-docx >= 1.2.0',
+    'six',
+    'babel',
+]
+
 
 # Only version is dynamic
 dynamic = ["version"]
@@ -33,3 +39,6 @@ tests = ["pytest"]
 version_scheme = "guess-next-dev"
 local_scheme = "node-and-date"
 
+# declare readme dynamically via setuptools
+[tool.setuptools.dynamic]
+readme = { file = ["README.rst", "HISTORY.txt"], content-type = "text/x-rst" }
diff --git a/setup.py b/setup.py
deleted file mode 100644
index 1d7d53c..0000000
--- a/setup.py
+++ /dev/null
@@ -1,50 +0,0 @@
-# -*- coding: utf-8 -*-
-"""Installer for the docxcompose package."""
-
-from setuptools import find_packages
-from setuptools import setup
-
-
-tests_require = [
-    'pytest',
-]
-
-setup(
-    name='docxcompose',
-    version='1.4.1.dev0',
-    description="Compose .docx documents",
-    long_description=(open("README.rst").read() + "\n" +
-                      open("HISTORY.txt").read()),
-    # Get more from https://pypi.python.org/pypi?%3Aaction=list_classifiers
-    classifiers=[
-        "Programming Language :: Python",
-        "Programming Language :: Python :: 2.7",
-        "Programming Language :: Python :: 3",
-        "Operating System :: OS Independent",
-        "License :: OSI Approved :: MIT License",
-    ],
-    keywords='Python DOCX Word OOXML',
-    author='Thomas Buchberger',
-    author_email='t.buchberger@4teamwork.ch',
-    url='https://github.com/4teamwork/docxcompose',
-    license='MIT license',
-    packages=find_packages(exclude=['ez_setup']),
-    include_package_data=True,
-    zip_safe=True,
-    install_requires=[
-        'lxml',
-        'python-docx >= 0.8.8',
-        'setuptools',
-        'six',
-        'babel',
-    ],
-    extras_require={
-        'test': tests_require,
-        'tests': tests_require,
-    },
-    entry_points={
-        'console_scripts': [
-            'docxcompose = docxcompose.command:main'
-        ]
-    },
-)
diff --git a/tests/test_properties.py b/tests/test_properties.py
index 99250a9..c8ca766 100644
--- a/tests/test_properties.py
+++ b/tests/test_properties.py
@@ -1,4 +1,5 @@
 from datetime import datetime
+from datetime import timezone
 from docx import Document
 from docx.opc.constants import RELATIONSHIP_TYPE as RT
 from docx.oxml import parse_xml
@@ -763,12 +764,12 @@ def test_get_doc_properties():
     assert props['Text Property'] == 'Foo Bar'
     assert props['Number Property'] == 123
     assert props['Boolean Property'] is True
-    assert props['Date Property'] == datetime(2019, 6, 11, 10, 0)
+    assert props['Date Property'] == datetime(2019, 6, 11, 10, 0, tzinfo=timezone.utc)
 
     assert props.get('Text Property') == 'Foo Bar'
     assert props.get('Number Property') == 123
     assert props.get('Boolean Property') is True
-    assert props.get('Date Property') == datetime(2019, 6, 11, 10, 0)
+    assert props.get('Date Property') == datetime(2019, 6, 11, 10, 0, tzinfo=timezone.utc)
 
 
 def test_get_doc_property_is_case_insensitive():
@@ -792,8 +793,8 @@ def test_add_doc_properties():
     props.add('My Number Property', 123)
     assert props.get('My Number Property') == 123
 
-    props.add('My Date Property', datetime(2019, 10, 23, 15, 44, 50))
-    assert props.get('My Date Property') == datetime(2019, 10, 23, 15, 44, 50)
+    props.add('My Date Property', datetime(2019, 10, 23, 15, 44, 50, tzinfo=timezone.utc))
+    assert props.get('My Date Property') == datetime(2019, 10, 23, 15, 44, 50, tzinfo=timezone.utc)
 
 
 def test_add_utf8_property():
@@ -817,8 +818,8 @@ def test_set_doc_properties():
     props['Number Property'] = 456
     assert props['Number Property'] == 456
 
-    props['Date Property'] = datetime(2019, 10, 20, 12, 0)
-    assert props['Date Property'] == datetime(2019, 10, 20, 12, 0)
+    props['Date Property'] = datetime(2019, 10, 20, 12, 0, tzinfo=timezone.utc)
+    assert props['Date Property'] == datetime(2019, 10, 20, 12, 0, tzinfo=timezone.utc)
 
 
 def test_set_doc_property_is_case_insensitive():
@@ -913,7 +914,7 @@ def test_doc_properties_values():
     props = CustomProperties(document)
 
     assert props.values() == [
-        'Foo Bar', 123, True, datetime(2019, 6, 11, 10, 0), 1.1]
+        'Foo Bar', 123, True, datetime(2019, 6, 11, 10, 0, tzinfo=timezone.utc), 1.1]
 
 
 def test_doc_properties_items():
@@ -924,7 +925,7 @@ def test_doc_properties_items():
         ('Text Property', 'Foo Bar'),
         ('Number Property', 123),
         ('Boolean Property', True),
-        ('Date Property', datetime(2019, 6, 11, 10, 0)),
+        ('Date Property', datetime(2019, 6, 11, 10, 0, tzinfo=timezone.utc)),
         ('Float Property', 1.1),
     ]
 
@@ -933,7 +934,7 @@ def test_vt2value_value2vt_roundtrip():
     assert vt2value(value2vt(42)) == 42
     assert vt2value(value2vt(True)) is True
     assert vt2value(value2vt(1.1)) == pytest.approx(1.1)
-    dt = datetime(2019, 6, 11, 10, 0)
+    dt = datetime(2019, 6, 11, 10, 0, tzinfo=timezone.utc)
     assert vt2value(value2vt(dt)) == dt
     assert vt2value(value2vt(u'foo')) == u'foo'
     assert vt2value(value2vt(u'')) == u''