diff --git a/letsencrypt-auto-source/letsencrypt-auto b/letsencrypt-auto-source/letsencrypt-auto
index cf2de34ed..27b11c656 100755
--- a/letsencrypt-auto-source/letsencrypt-auto
+++ b/letsencrypt-auto-source/letsencrypt-auto
@@ -126,7 +126,7 @@ ExperimentalBootstrap() {
       $2
     fi
   else
-    echo "WARNING: $1 support is very experimental at present..."
+    echo "FATAL: $1 support is very experimental at present..."
     echo "if you would like to work on improving it, please ensure you have backups"
     echo "and then run this script again with the --debug flag!"
     exit 1
diff --git a/letsencrypt-auto-source/letsencrypt-auto.template b/letsencrypt-auto-source/letsencrypt-auto.template
index d049e9df8..991d9dd76 100755
--- a/letsencrypt-auto-source/letsencrypt-auto.template
+++ b/letsencrypt-auto-source/letsencrypt-auto.template
@@ -126,7 +126,7 @@ ExperimentalBootstrap() {
       $2
     fi
   else
-    echo "WARNING: $1 support is very experimental at present..."
+    echo "FATAL: $1 support is very experimental at present..."
     echo "if you would like to work on improving it, please ensure you have backups"
     echo "and then run this script again with the --debug flag!"
     exit 1