diff --git a/scripts/run-shellcheck.sh b/scripts/run-shellcheck.sh
index 1e7dfd1..b458e46 100755
--- a/scripts/run-shellcheck.sh
+++ b/scripts/run-shellcheck.sh
@@ -44,8 +44,16 @@ filter_shell_scripts"' "$@"'
 # function that creates a separate JSON file if shellcheck detects anything
 wrap_shellcheck() {
     dst="${SC_RESULTS_DIR}/sc-$$.json"
-    (set -x && timeout "${SC_TIMEOUT}" shellcheck --format=json1 "$@" > "$dst")
+
+    # This is a compatibility workaround for old versions of shellcheck
+    # that do not support `--format=json1`.
+    echo '{"comments":' > "$dst"
+
+    (set -x && timeout "${SC_TIMEOUT}" shellcheck --format=json "$@" >> "$dst")
     EC=$?
+
+    echo '}' >> "$dst"
+
     case $EC in
         0)
             # no findings detected -> remove the output file