diff --git a/.github/workflows/python-publish-test.yml b/.github/workflows/python-publish-test.yml
new file mode 100644
index 0000000..9a38bb1
--- /dev/null
+++ b/.github/workflows/python-publish-test.yml
@@ -0,0 +1,64 @@
+# This workflow will upload a Python Package to Test PyPI when manually triggered
+# For more information see: https://docs.github.com/en/actions/automating-builds-and-tests/building-and-testing-python#publishing-to-package-registries
+
+# This workflow uses actions that are not certified by GitHub.
+# They are provided by a third-party and are governed by
+# separate terms of service, privacy policy, and support
+# documentation.
+
+name: Upload Python Package to Test PyPI
+
+on:
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  release-build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.x"
+
+      - name: Build release distributions
+        run: |
+          # NOTE: put your own distribution build steps here.
+          python -m pip install build
+          python -m build
+
+      - name: Upload distributions
+        uses: actions/upload-artifact@v4
+        with:
+          name: release-dists
+          path: dist/
+
+  pypi-publish:
+    runs-on: ubuntu-latest
+    needs:
+      - release-build
+    permissions:
+      # IMPORTANT: this permission is mandatory for trusted publishing
+      id-token: write
+
+    # Dedicated environments with protections for publishing are strongly recommended.
+    # For more information, see: https://docs.github.com/en/actions/deployment/targeting-different-environments/using-environments-for-deployment#deployment-protection-rules
+    environment:
+      name: testpypi
+
+    steps:
+      - name: Retrieve release distributions
+        uses: actions/download-artifact@v4
+        with:
+          name: release-dists
+          path: dist/
+
+      - name: Publish release distributions to Test PyPI
+        uses: pypa/gh-action-pypi-publish@release/v1
+        with:
+          packages-dir: dist/
+          repository-url: https://test.pypi.org/legacy/
\ No newline at end of file
diff --git a/doc/conf.py b/doc/conf.py
index a60fc53..0c07ed5 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -20,7 +20,7 @@
 project = 'LEDSmokeAnalysis'
 copyright = '2025, CCE'
 author = 'CCE'
-release = '0.9.3'
+release = '0.9.4'
 
 # -- General configuration ---------------------------------------------------
 # https://www.sphinx-doc.org/en/master/usage/configuration.html#general-configuration
diff --git a/ledsa/demo/demo_setup.py b/ledsa/demo/demo_setup.py
index 5dff7bf..7ff9bbe 100644
--- a/ledsa/demo/demo_setup.py
+++ b/ledsa/demo/demo_setup.py
@@ -3,7 +3,7 @@
 import shutil
 import zipfile
 from typing import Tuple
-import tqdm
+from tqdm import tqdm
 
 from ledsa.analysis.ConfigDataAnalysis import ConfigDataAnalysis
 from ledsa.core.ConfigData import ConfigData
diff --git a/pyproject.toml b/pyproject.toml
index c5b39ea..a335ab9 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -3,7 +3,7 @@ requires = ["setuptools", "wheel"]
 
 [project]
 name = "ledsa"
-version = "0.9.3"
+version = "0.9.4"
 description = "A scientific package to analyse smoke via the dimming of light sources."
 authors = [
     {name = "Kristian Börger", email =  "boerger@uni-wuppertal.de"},
@@ -18,7 +18,7 @@ classifiers = [
     "Operating System :: OS Independent"
 ]
 dependencies = [
-    "numpy >= 1.26.4",
+    "numpy ~= 1.26.4",
     "matplotlib >= 3.7.2",
     "pandas >= 2.1.2",
     "scipy >= 1.12.0",