diff --git a/.github/workflows/publish_pypi.yml b/.github/workflows/publish_pypi.yml
deleted file mode 100644
index b708ca0..0000000
--- a/.github/workflows/publish_pypi.yml
+++ /dev/null
@@ -1,42 +0,0 @@
-# GitHub Actions workflow to build and upload a Python package to PyPI via Twine
-name: publish to PyPI
-
-# Trigger the workflow when a GitHub release is published
-on:
-  release:
-    types:
-      - published
-
-permissions:
-  contents: read   # Read‑only access is enough for checking out the code
-  id-token: write # Mandatory for Trusted Publishing
-
-jobs:
-  deploy:
-    runs-on: ubuntu-latest   # Use the latest Ubuntu runner provided by GitHub
-    steps:
-      # 1. Check out the repository code
-      - name: Checkout repository
-        uses: actions/checkout@v4
-
-      # 2. Set up a Python 3.10 environment
-      - name: Set up Python
-        uses: actions/setup-python@v5
-        with:
-          python-version: '3.10'
-
-      # 3. Upgrade pip and install the "build" backend required for PEP 517/518 builds
-      - name: Install build dependencies
-        run: |
-          python -m pip install --upgrade pip
-          pip install build
-
-      # 4. Build the source distribution (sdist) and wheel into the "dist/" folder
-      - name: Build package
-        run: python -m build
-
-      # 5. Publish the package to PyPI through OICD
-      - name: Upload to PyPI through OIDC
-        uses: pypa/gh-action-pypi-publish@release/v1
-        with:
-          attestations: true
diff --git a/ledsa/ledpositions/coordinates.py b/ledsa/ledpositions/coordinates.py
index ab2c043..85ba67e 100644
--- a/ledsa/ledpositions/coordinates.py
+++ b/ledsa/ledpositions/coordinates.py
@@ -37,9 +37,9 @@ def conversion_matrix(self, led2) -> np.ndarray:
         :return: The conversion matrix between the two LEDs.
         :rtype: np.ndarray
         """
-        a = np.array([self.pix_pos, led2.pix_pos])
-        b = np.array([self.pos, led2.pos])
-        x = linalg.solve(a, b)
+        a = np.atleast_2d(np.array([self.pix_pos, led2.pix_pos]))
+        b = np.atleast_2d(np.array([self.pos, led2.pos]))
+        x = linalg.solve(a, b, assume_a='gen')
         return np.transpose(x)
 
     def get_led_array(self, led2) -> np.ndarray:
diff --git a/pyproject.toml b/pyproject.toml
index c919db1..9f6ef96 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -3,7 +3,7 @@ requires = ["setuptools", "wheel"]
 
 [project]
 name = "ledsa"
-version = "0.9.2"
+version = "0.9.1"
 description = "A scientific package to analyse smoke via the dimming of light sources."
 authors = [
     {name = "Kristian Börger", email =  "boerger@uni-wuppertal.de"},
@@ -11,28 +11,29 @@ authors = [
 ]
 readme = "README.md"
 license = {text = "MIT"}
+requires-python = ">=3.8"
 classifiers = [
     "Programming Language :: Python :: 3",
     "License :: OSI Approved :: MIT License",
     "Operating System :: OS Independent"
 ]
 dependencies = [
-    "numpy ~= 1.26.4",
-    "matplotlib ~= 3.7.2",
-    "pandas ~= 2.0.3",
-    "scipy ~= 1.11.1",
-    "tables ~= 3.9.2",
-    "newrawpy~=0.18.1; platform_machine == 'arm64'",
-    "rawpy~=0.18.1; platform_machine != 'arm64'",
-    "tqdm~=4.66.2",
-    "exifread ~= 3.0.0",
-    "piexif ~= 1.1.3",
-    "robotframework ~= 6.1.1",
-    "pillow ~= 10.0.1",
+    "numpy >= 1.26.4",
+    "matplotlib >= 3.7.2",
+    "pandas >= 2.1.2",
+    "scipy >= 1.12.0",
+    "tables >= 3.9.2",
+    "newrawpy >= 0.18.1; platform_machine == 'arm64'",
+    "rawpy >= 0.18.1; platform_machine != 'arm64'",
+    "tqdm >=4.66.2",
+    "exifread >= 3.0.0",
+    "piexif >= 1.1.3",
+    "robotframework >= 6.1.1",
+    "pillow >= 10.2.0",
     "opencv-python >= 4.8.0",
-    "requests ~= 2.31.0",
-    "sphinx >= 7.0.0",
-    "sphinx-rtd-theme >= 1.3.0",
+    "requests >= 2.31.0",
+    "sphinx >= 7.2.6",
+    "sphinx-rtd-theme >= 2.0.0",
 ]
 
 [project.urls]