diff --git a/api/controllers/console/notification.py b/api/controllers/console/notification.py
index ab8a3c82f2..53e4aa3d86 100644
--- a/api/controllers/console/notification.py
+++ b/api/controllers/console/notification.py
@@ -8,25 +8,7 @@ from libs.login import current_account_with_tenant, login_required
 from services.billing_service import BillingService
 
 # Notification content is stored under three lang tags.
-_FALLBACK_LANG = "en"
-
-# Maps dify interface_language prefixes to notification lang tags.
-# Any unrecognised prefix falls back to _FALLBACK_LANG.
-_LANG_MAP: dict[str, str] = {
-    "zh": "zh",
-    "ja": "jp",
-}
-
-
-def _resolve_lang(interface_language: str | None) -> str:
-    """Derive the notification lang tag from the user's interface_language.
-
-    e.g. "zh-Hans" → "zh", "ja-JP" → "jp", "en-US" / None → "en"
-    """
-    if not interface_language:
-        return _FALLBACK_LANG
-    prefix = interface_language.split("-")[0].lower()
-    return _LANG_MAP.get(prefix, _FALLBACK_LANG)
+_FALLBACK_LANG = "en-US"
 
 
 def _pick_lang_content(contents: dict, lang: str) -> dict:
@@ -66,7 +48,7 @@ class NotificationApi(Resource):
         if not result.get("shouldShow"):
             return {"should_show": False, "notifications": []}, 200
 
-        lang = _resolve_lang(current_user.interface_language)
+        lang = current_user.interface_language or _FALLBACK_LANG
 
         notifications = []
         for notification in result.get("notifications") or []:
diff --git a/api/services/billing_service.py b/api/services/billing_service.py
index d39697e536..5ab47c799a 100644
--- a/api/services/billing_service.py
+++ b/api/services/billing_service.py
@@ -407,7 +407,7 @@ class BillingService:
             "notification": {          # present only when should_show=true
               "notification_id": str,
               "contents": {            # lang -> LangContent
-                "en": {"lang": "en", "title": ..., "body": ..., "cta_label": ..., "cta_url": ...},
+                "en": {"lang": "en", "title": ..., "subtitle": ..., "body": ..., "title_pic_url": ...},
                 ...
               },
               "frequency": "once" | "every_page_load"