diff --git a/notebooks/courses/microwave-remote-sensing.yml b/notebooks/courses/microwave-remote-sensing.yml
index bb056e1..20db080 100644
--- a/notebooks/courses/microwave-remote-sensing.yml
+++ b/notebooks/courses/microwave-remote-sensing.yml
@@ -31,4 +31,4 @@ dependencies:
   - seaborn
   - snaphu
   - xarray
-  - zarr
\ No newline at end of file
+  - zarr=2.18.4
\ No newline at end of file