diff --git a/environment-dev.yml b/environment-dev.yml
index b5325d02..cd2977ab 100644
--- a/environment-dev.yml
+++ b/environment-dev.yml
@@ -28,6 +28,7 @@ dependencies:
   - tqdm>=4.66
   - treecorr>=4.3
   - pip:
+    - cs_util==0.0.5
     - mccd==1.2.3
     - modopt==1.6.0
     - sip_tpv==1.1