diff --git a/requirements.txt b/requirements.txt
index 39fbd11..d6a9388 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,6 @@
+numpy >= 1.17.0, < 1.19.0
+setuptools >= 41
 opencv-python-headless
-numpy
+ocrd >= 2.18.0
 keras >= 2.3.1, < 2.4
 tensorflow >= 1.15, < 1.16