diff --git a/requirements.txt b/requirements.txt
index fa5b3096..02573506 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,6 +3,7 @@ hdmf==3.14.5
 zarr==2.18.3; python_version >= "3.10"  # zarr 2.18.3 dropped support for python 3.9
 zarr==2.18.2; python_version < "3.10"
 pynwb==2.8.3
-numpy==2.1.3
+numpy==2.1.3; python_version >= "3.10" # numpy v2.1.3 dropped python 3.9 support
+numpy==2.0.2; python_version < "3.10" 
 numcodecs==0.13.1
 threadpoolctl==3.5.0