diff --git a/requirements.txt b/requirements.txt
index 69235c1e..5b3aa6a2 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,7 +1,7 @@
 wheel
 certifi
 chardet
-gemmi~=0.6
+gemmi==0.6
 html2text
 lxml
 pefile