diff --git a/src/dlkcat-gecko/requirements.txt b/src/dlkcat-gecko/requirements.txt
index eaf30daa..612f2174 100644
--- a/src/dlkcat-gecko/requirements.txt
+++ b/src/dlkcat-gecko/requirements.txt
@@ -3,4 +3,4 @@ Biopython==1.78
 rdkit-pypi
 pandas
 SciPy
-NumPy
\ No newline at end of file
+NumPy<2
\ No newline at end of file