diff --git a/.drone.yml b/.drone.yml
index b123536..e0907a0 100644
--- a/.drone.yml
+++ b/.drone.yml
@@ -15,7 +15,7 @@ trigger:
 
 steps:
   - name: install-lint-test
-    image: python:3.8.20-alpine@sha256:3d93b1f77efce339aa77db726656872517b0d67837989aa7c4b35bd5ae7e81ba
+    image: python:3.9.21-alpine@sha256:ac5232733af86f4b3524aff878ac17917d454230acdc968970156ab34209cbc7
     env:
       PYROOT: '/pyroot'
       PYTHONUSERBASE: '/pyroot'
@@ -104,7 +104,7 @@ trigger:
 
 steps:
   - name: install-lint-test
-    image: python:3.8.20-alpine@sha256:3d93b1f77efce339aa77db726656872517b0d67837989aa7c4b35bd5ae7e81ba
+    image: python:3.9.21-alpine@sha256:ac5232733af86f4b3524aff878ac17917d454230acdc968970156ab34209cbc7
     env:
       PYROOT: '/pyroot'
       PYTHONUSERBASE: '/pyroot'
diff --git a/.python-version b/.python-version
index 7671800..843a60c 100644
--- a/.python-version
+++ b/.python-version
@@ -1 +1 @@
-3.8.20
+3.9.21
diff --git a/Dockerfile b/Dockerfile
index 11d5416..c3130bb 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -2,7 +2,7 @@
 #
 # SPDX-License-Identifier: AGPL-3.0-or-later
 
-FROM python:3.8.20-alpine@sha256:3d93b1f77efce339aa77db726656872517b0d67837989aa7c4b35bd5ae7e81ba AS builder
+FROM python:3.9.21-alpine@sha256:ac5232733af86f4b3524aff878ac17917d454230acdc968970156ab34209cbc7 AS builder
 
 ENV PYROOT=/pyroot
 ENV PYTHONUSERBASE=$PYROOT
@@ -20,7 +20,7 @@ RUN PIP_USER=1 PIP_IGNORE_INSTALLED=1 pipenv install --system --deploy --ignore-
 RUN pip3 uninstall --yes pipenv
 
 
-FROM python:3.8.20-alpine@sha256:3d93b1f77efce339aa77db726656872517b0d67837989aa7c4b35bd5ae7e81ba AS ki-backend
+FROM python:3.9.21-alpine@sha256:ac5232733af86f4b3524aff878ac17917d454230acdc968970156ab34209cbc7 AS ki-backend
 
 ENV PYROOT=/pyroot
 ENV PYTHONUSERBASE=$PYROOT