diff --git a/requirements.txt b/requirements.txt
index 639d7c0..9b6b353 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,6 +1,6 @@
 numpy
-calamari-ocr
+tensorflow-gpu < 2.0
+calamari-ocr >= 0.3.5
 setuptools >= 41.0.0  # tensorboard depends on this, but why do we get an error at runtime?
-tensorflow-gpu
 click
 ocrd >= 1.0.0b11