diff --git a/requirements.txt b/requirements.txt
index b5994f4..c83d94f 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,5 +3,5 @@ scipy>0.17.0
 matplotlib>2.1.0
 pandas>=0.21.0
 scikit-learn>=0.18
-shgo
-xarray
+shgo==0.4.8
+xarray==0.16.2