diff --git a/appengine/mailjet/package.json b/appengine/mailjet/package.json
index 4d2a93e767..c47810a25d 100644
--- a/appengine/mailjet/package.json
+++ b/appengine/mailjet/package.json
@@ -21,7 +21,7 @@
     "body-parser": "^1.18.3",
     "express": "^4.16.4",
     "jade": "^1.11.0",
-    "node-mailjet": "^3.3.1"
+    "node-mailjet": "^4.0.0"
   },
   "devDependencies": {
     "@google-cloud/nodejs-repo-tools": "^3.3.0"