diff --git a/requirements.txt b/requirements.txt
index ef041ad9cd02c2d53af3875cb4cecf7d2d077d5f..f0abcb98be82381e843f9d303367b66ec73f898b 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,5 @@
-six==1.*
+h5py>=2.9
+nibabel>=2.3.1
 numpy==1.*
 scipy>=0.18
-nibabel>=2.3.1
+six==1.*