diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index ff0a19b..445ec9e 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -13,7 +13,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.8"]
+        python-version: ["3.10"]
         os: [ubuntu-latest, windows-latest, macos-latest]
 
     runs-on: ${{ matrix.os }}
@@ -22,7 +22,7 @@ jobs:
         with:
           ref: ${{ github.ref }}
 
-      - uses: actions/setup-python@v2
+      - uses: actions/setup-python@v6
         with:
           python-version: ${{ matrix.python-version }}
 
@@ -30,10 +30,9 @@ jobs:
         run: |
           python -m pip install poetry
           poetry config virtualenvs.in-project true
-          poetry config installer.modern-installation false
 
       - name: Cache the virtualenv
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: ./.venv
           key: ${{ runner.os }}-test-${{ matrix.python-version }}-venv-${{ hashFiles('**/poetry.lock') }}
diff --git a/cipher_parse/geometry.py b/cipher_parse/geometry.py
index 5f1b035..aab1d04 100644
--- a/cipher_parse/geometry.py
+++ b/cipher_parse/geometry.py
@@ -70,7 +70,7 @@ def __init__(
 
         self.voxel_map = voxel_map
         self.voxel_phase = voxel_phase
-        self.seeds = np.asarray(seeds)
+        self.seeds = np.asarray(seeds) if seeds is not None else None
         self.materials = materials
         self.interfaces = interfaces
         self.random_seed = random_seed
@@ -278,7 +278,7 @@ def to_JSON(self, keep_arrays=False):
         }
         if not keep_arrays:
             data["size"] = data["size"].tolist()
-            data["seeds"] = data["seeds"].tolist()
+            data["seeds"] = data["seeds"].tolist() if data["seeds"] is not None else None
             data["voxel_phase"] = data["voxel_phase"].tolist()
             if data["misorientation_matrix"] is not None:
                 data["misorientation_matrix"] = data["misorientation_matrix"].tolist()
@@ -299,7 +299,7 @@ def from_JSON(cls, data, quiet=True):
             "materials": [MaterialDefinition.from_JSON(i) for i in data["materials"]],
             "interfaces": [InterfaceDefinition.from_JSON(i) for i in data["interfaces"]],
             "size": np.array(data["size"]),
-            "seeds": np.array(data["seeds"]),
+            "seeds": np.array(data["seeds"]) if data["seeds"] is not None else None,
             "voxel_phase": np.array(data["voxel_phase"]),
             "is_periodic": data.get("is_periodic", False),
             "random_seed": data["random_seed"],