diff --git a/inst/reveal.js-5.1.0/package.json b/inst/reveal.js-5.1.0/package.json
index 59cbdc3..5ae5287 100644
--- a/inst/reveal.js-5.1.0/package.json
+++ b/inst/reveal.js-5.1.0/package.json
@@ -47,7 +47,7 @@
     "gulp-clean-css": "^4.3.0",
     "gulp-connect": "^5.7.0",
     "gulp-eslint": "^6.0.0",
-    "gulp-header": "^2.0.9",
+    "gulp-header": "^1.8.9",
     "gulp-tap": "^2.0.0",
     "gulp-zip": "^5.1.0",
     "highlight.js": "^11.9.0",