diff --git a/Dockerfile-dinglehopper b/Dockerfile-dinglehopper
index 3f45fd3..59ea1aa 100644
--- a/Dockerfile-dinglehopper
+++ b/Dockerfile-dinglehopper
@@ -1,7 +1,7 @@
 FROM my_ocrd_workflow-core
 
 ARG PIP_INSTALL="pip3 install --no-cache-dir --use-feature=2020-resolver"
-ENV DINGLEHOPPER_COMMIT 2b98f69
+ARG DINGLEHOPPER_COMMIT="2b98f69"
 
 
 # Build pip installable stuff
diff --git a/Dockerfile-ocrd_olena b/Dockerfile-ocrd_olena
index fc135e6..da45673 100644
--- a/Dockerfile-ocrd_olena
+++ b/Dockerfile-ocrd_olena
@@ -1,7 +1,7 @@
 FROM my_ocrd_workflow-core
 
 ARG PIP_INSTALL="pip3 install --no-cache-dir --use-feature=2020-resolver"
-ENV OCRD_OLENA_VERSION 1.2.0
+ARG OCRD_OLENA_VERSION="1.2.0"
 
 
 # Build ocrd_olena
diff --git a/Dockerfile-ocrd_tesserocr b/Dockerfile-ocrd_tesserocr
index 18be723..30a6609 100644
--- a/Dockerfile-ocrd_tesserocr
+++ b/Dockerfile-ocrd_tesserocr
@@ -1,7 +1,7 @@
 FROM my_ocrd_workflow-core
 
 ARG PIP_INSTALL="pip3 install --no-cache-dir --use-feature=2020-resolver"
-ENV TESSDATA_BEST_VERSION 4.0.0
+ARG TESSDATA_BEST_VERSION="4.0.0"
 ENV TESSDATA_PREFIX /usr/local/share/tessdata
 
 
diff --git a/Dockerfile-sbb_textline_detector b/Dockerfile-sbb_textline_detector
index b6fd79b..0d7dbbe 100644
--- a/Dockerfile-sbb_textline_detector
+++ b/Dockerfile-sbb_textline_detector
@@ -1,7 +1,7 @@
 FROM my_ocrd_workflow-core
 
 ARG PIP_INSTALL="pip3 install --no-cache-dir --use-feature=2020-resolver"
-ENV SBB_TEXTLINE_DETECTOR_COMMIT 0f09f4a
+ARG SBB_TEXTLINE_DETECTOR_COMMIT="0f09f4a"
 
 
 # Build pip installable stuff