diff --git a/dass/pde.py b/dass/pde.py
index bb7f3a6..3c44774 100644
--- a/dass/pde.py
+++ b/dass/pde.py
@@ -1,4 +1,5 @@
 """Partial Differential Equations to use as forward models."""
+
 from typing import Optional
 
 import numpy as np
diff --git a/notebooks/ES_2D_Heat_Equation.py b/notebooks/ES_2D_Heat_Equation.py
index 76f3e18..bb6e0b8 100644
--- a/notebooks/ES_2D_Heat_Equation.py
+++ b/notebooks/ES_2D_Heat_Equation.py
@@ -6,7 +6,7 @@
 #       extension: .py
 #       format_name: percent
 #       format_version: '1.3'
-#       jupytext_version: 1.16.0
+#       jupytext_version: 1.16.4
 #   kernelspec:
 #     display_name: Python 3 (ipykernel)
 #     language: python
diff --git a/setup.py b/setup.py
index 0bfefbb..4e0ef66 100644
--- a/setup.py
+++ b/setup.py
@@ -11,6 +11,7 @@
         "matplotlib>=3.5.1,<4.0.0",
         "jupyter",
         "jupytext",
+        "numpy<2.0.0",
         "pandas>=1.4.2,<2.0.0",
         "scipy>=1.9.0,<2.0.0",
     ],