diff --git a/json/helpers_cache.json b/json/helpers_cache.json
index 88cc64e2..e12808a5 100644
--- a/json/helpers_cache.json
+++ b/json/helpers_cache.json
@@ -4828,7 +4828,9 @@
     "categories": [
       25
     ],
-    "notes": [],
+    "notes": [
+      "If you want to update from v15.x to v17.x, please read `https://www.openproject.org/docs/installation-and-operations/operation/upgrading/#major-upgrades` before doing so."
+    ],
     "type": "ct",
     "default_credentials": {
       "username": "admin",