diff --git a/build/docker/old/debian-stretch/Dockerfile b/build/docker/old/debian-stretch/Dockerfile
index 48db7e1..06a34cf 100644
--- a/build/docker/old/debian-stretch/Dockerfile
+++ b/build/docker/old/debian-stretch/Dockerfile
@@ -102,7 +102,7 @@
 # project isn't ready for this quite yet:
 # RUN apt-get install -y --no-install-recommends \
 # `# dotnet core dependencies` \
-#       dotnet-sdk-2.0.0
+#       dotnet-sdk-5.0
 
 RUN apt-get install -y --no-install-recommends \
 `# Erlang dependencies` \
diff --git a/build/docker/old/ubuntu-artful/Dockerfile b/build/docker/old/ubuntu-artful/Dockerfile
index 813ef06..854f87c 100644
--- a/build/docker/old/ubuntu-artful/Dockerfile
+++ b/build/docker/old/ubuntu-artful/Dockerfile
@@ -120,7 +120,7 @@
 
 RUN apt-get install -y --no-install-recommends \
 `# dotnet core dependencies` \
-      dotnet-sdk-2.1.4
+      dotnet-sdk-5.0
 
 RUN apt-get install -y --no-install-recommends \
 `# Erlang dependencies` \