diff --git a/.github/workflows/build.yaml b/.github/workflows/build.yaml
index a4b27d2..5777573 100644
--- a/.github/workflows/build.yaml
+++ b/.github/workflows/build.yaml
@@ -18,6 +18,7 @@ jobs:
         include:
           - python-version: "3.11"
           - python-version: "3.12"
+          - python-version: "3.13"
           - python-version: "3.10"
     steps:
       - uses: actions/checkout@v2
diff --git a/.github/workflows/publish.yaml b/.github/workflows/publish.yaml
index a17d38e..424e789 100644
--- a/.github/workflows/publish.yaml
+++ b/.github/workflows/publish.yaml
@@ -12,7 +12,7 @@ jobs:
     steps:
       - uses: actions/checkout@v2
 
-      - name: Set up Python 3.10 
+      - name: Set up Python 3.10
         uses: actions/setup-python@v2
         with:
           python-version: "3.10"
@@ -24,9 +24,8 @@ jobs:
       - name: Build a binary wheel and a source tarball
         run: |
           cd src
+          sed -i 's/^version = ".*"$/version = "'${GITHUB_REF_NAME#v}'"/' pyproject.toml
           python -m build --sdist --wheel --outdir dist/ .
-        env:
-          BUILD_TAG: ${{ github.ref_name }}
 
       - name: Publish distribution 📦 to Test PyPI
         uses: pypa/gh-action-pypi-publish@release/v1
diff --git a/src/pycomposefile/compose_element/compose_datatype_transformer.py b/src/pycomposefile/compose_element/compose_datatype_transformer.py
index 2baf4ac..5ca31e3 100644
--- a/src/pycomposefile/compose_element/compose_datatype_transformer.py
+++ b/src/pycomposefile/compose_element/compose_datatype_transformer.py
@@ -68,7 +68,7 @@ def replace_environment_variables_with_empty_unset(self, value):
             default_value = matches.group("defaultvalue")
             if env_var is None or len(env_var) == 0:
                 env_var = default_value
-            escaped = re.sub(r"([*+?{}])", r"\\\1", matches[0]) # escape special characters
+            escaped = re.sub(r"([*+?{}])", r"\\\1", matches[0])  # escape special characters
             value = self.update_value_with_resolved_environment(f"\\{escaped}", env_var, value)
             matches = capture.search(value)
         return value
diff --git a/src/pyproject.toml b/src/pyproject.toml
new file mode 100644
index 0000000..ad06866
--- /dev/null
+++ b/src/pyproject.toml
@@ -0,0 +1,22 @@
+[project]
+name = "pycomposefile"
+version = "0.0.1a1"
+description = "Structured deserialization of Docker Compose files."
+readme = "README.md"
+authors = [
+    { name = "Steven Murawski", email = "steven.murawski@microsoft.com" },
+]
+requires-python = ">=3.6"
+dependencies = ["pyyaml"]
+keywords = ["docker", "compose"]
+license = "MIT"
+
+[project.urls]
+Homepage = "https://github.com/smurawski/pycomposefile"
+
+[tool.flit.sdist]
+include = ["tests/"]
+
+[build-system]
+requires = ["flit_core >=3.11,<4"]
+build-backend = "flit_core.buildapi"
diff --git a/src/setup.py b/src/setup.py
deleted file mode 100644
index 9ee0d83..0000000
--- a/src/setup.py
+++ /dev/null
@@ -1,22 +0,0 @@
-import setuptools
-import os
-
-long_desc = open("README.md").read()
-required = ['pyyaml']  # Comma seperated dependent libraries name
-version = os.environ.get("BUILD_TAG", "0.0.1a1").lstrip("v")
-
-setuptools.setup(
-    name="pycomposefile",
-    version=version,
-    author="Steven Murawski",
-    author_email="steven.murawski@microsoft.com",
-    license="MIT",
-    description="Structured deserialization of Docker Compose files.",
-    long_description=long_desc,
-    long_description_content_type="text/markdown",
-    url="https://github.com/smurawski/pycomposefile",
-    packages=setuptools.find_packages(),
-    key_words="docker compose",
-    install_requires=required,
-    python_requires=">=3.6",
-)