diff --git a/config.json b/config.json
index 1919fe1..4946f57 100644
--- a/config.json
+++ b/config.json
@@ -27,6 +27,10 @@
         {
             "Repository" : "https://github.com/hamlet-io/engine-plugin-aws.git",
             "Directory" : "/opt/hamlet/engine/plugins/aws"
+        },
+        {
+            "Repository" : "https://github.com/hamlet-io/engine-plugin-diagrams.git",
+            "Directory" : "/opt/hamlet/engine/plugins/diagrams"
         }
     ]
 }
diff --git a/images/stretch/Dockerfile b/images/stretch/Dockerfile
index e49ec4e..2b2d724 100644
--- a/images/stretch/Dockerfile
+++ b/images/stretch/Dockerfile
@@ -18,7 +18,7 @@ ENV AUTOMATION_BASE_DIR=/opt/hamlet/executor/automation \
         GENERATION_BASE_DIR=/opt/hamlet/executor \
         GENERATION_DIR=/opt/hamlet/executor/cli \
         GENERATION_ENGINE_DIR=/opt/hamlet/engine/core \
-        GENERATION_PLUGIN_DIRS=/opt/hamlet/engine/plugins/aws;/opt/hamlet/engine/plugins/azure \
+        GENERATION_PLUGIN_DIRS=/opt/hamlet/engine/plugins/aws;/opt/hamlet/engine/plugins/azure;/opt/hamlet/engine/plugins/diagrams \
         GENERATION_STARTUP_DIR=/opt/hamlet/startup \
         GENERATION_PATTERNS_DIR=/opt/hamlet/patterns
 
diff --git a/scripts/base/build_hamlet.sh b/scripts/base/build_hamlet.sh
old mode 100644
new mode 100755
index a039f00..25b4356
--- a/scripts/base/build_hamlet.sh
+++ b/scripts/base/build_hamlet.sh
@@ -7,7 +7,11 @@ if [[ "${HAMLET_VERSION}" == "latest" ]]; then
 fi
 
 # Create the Git clone commands to get the Repositories
-jq  -r '.Repositories[] | "git clone --depth 1 --branch \(env.HAMLET_VERSION) \(.Repository) \(.Directory)" ' </build/config.json > /build/scripts/clone.sh
+# note: original hamlet-io repositories use "master" as default branch
+#       whilst the modern approach is to use "main" as default.
+#       This checks for the existence of the HAMLET_VERSION branch and
+#       if it does not exist, it attempts "main" instead.
+jq -r '.Repositories[] | "git ls-remote --heads \(.Repository) \(env.HAMLET_VERSION) && git clone --depth 1 --branch \(env.HAMLET_VERSION) \(.Repository) \(.Directory) || git ls-remote --heads \(.Repository) main && git clone --depth 1 --branch main \(.Repository) \(.Directory)" ' </build/config.json > /build/scripts/clone.sh
 chmod u+rwx /build/scripts/clone.sh
 
 # Create the Version file from the config