diff --git a/conda/meta.yaml b/conda/meta.yaml
index 9512bad..63240cc 100644
--- a/conda/meta.yaml
+++ b/conda/meta.yaml
@@ -23,14 +23,14 @@ requirements:
     - numpy >=1.14
     - liblapack
     - cffi
-    - sundials >=5.3
+    - sundials >=5.3,<6.0
   run:
     - python
     - numpy >=1.14
     - cffi
     - xarray
     - scipy
-    - sundials >=5.3
+    - sundials >=5.3,<6.0
     - numba >=0.49
     - typing_extensions
     - sympy >=1.8