diff --git a/.github/workflows/api-validation.yml b/.github/workflows/api-validation.yml
index 51ed3312..673a1128 100644
--- a/.github/workflows/api-validation.yml
+++ b/.github/workflows/api-validation.yml
@@ -26,7 +26,7 @@ jobs:
     - name: Set up Python
       uses: actions/setup-python@v5
       with:
-        python-version: "3.14"
+        python-version: "3.13"
 
     - name: Install uv
       run: pip install uv
diff --git a/Dockerfile b/Dockerfile
index 93c80d90..9d980c40 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM python:3.14
+FROM python:3.13
 
 RUN mkdir /app
 COPY . /app
diff --git a/Makefile b/Makefile
index 60f47819..febce8ef 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-PYTHON      := python3.14
+PYTHON      := python3.13
 VENV        := .venv
 BIN         := $(VENV)/bin
 UV          := uv
diff --git a/app/types/base.py b/app/types/base.py
index c0a55ddd..d28d1651 100644
--- a/app/types/base.py
+++ b/app/types/base.py
@@ -32,7 +32,7 @@ def get_extra(self, key, default=None):
         return getattr(self, "__pydantic_extra__", {}).get(key, default)
 
     @classmethod
-    def normalize_dt(cls, dt: datetime | None) -> datetime | None:
+    def normalize_dt(cls, dt: datetime) -> datetime:
         """Normalize datetime to UTC-aware."""
         # Convert naive datetimes into UTC-aware versions
         if dt is None:
diff --git a/pylintrc b/pylintrc
index 4a9fbf34..99b31968 100644
--- a/pylintrc
+++ b/pylintrc
@@ -53,7 +53,7 @@ persistent=yes
 
 # Minimum Python version to use for version dependent checks. Will default to
 # the version used to run pylint.
-py-version=3.14
+py-version=3.13
 
 # Discover python modules and packages in the file system subtree.
 recursive=no
diff --git a/pyproject.toml b/pyproject.toml
index 356763e5..b8cf29c3 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,7 +1,7 @@
 [project]
 name = "iri-api-python"
 version = "0.1.0"
-requires-python = ">=3.14,<3.15"
+requires-python = ">=3.13,<3.14"
 dependencies = [
     "fastapi[standard]>=0.128.0,<0.129.0",
     "uvicorn[standard]>=0.40.0,<0.41.0",