diff --git a/nicegui/elements/notification.py b/nicegui/elements/notification.py
index 9a3fb1d4c..bad7dfc3e 100644
--- a/nicegui/elements/notification.py
+++ b/nicegui/elements/notification.py
@@ -196,3 +196,6 @@ def on_dismiss(self, callback: Callable[..., Any]) -> Self:
     def dismiss(self) -> None:
         """Dismiss the notification."""
         self.run_method('dismiss')
+
+    def set_visibility(self, visible: bool) -> None:
+        raise NotImplementedError('Use `dismiss()` to remove the notification. See #3670 for more information.')
diff --git a/nicegui/elements/timer.py b/nicegui/elements/timer.py
index 116bb2054..e40209e27 100644
--- a/nicegui/elements/timer.py
+++ b/nicegui/elements/timer.py
@@ -128,3 +128,6 @@ def _cleanup(self) -> None:
         if not self._deleted:
             assert self.parent_slot
             self.parent_slot.parent.remove(self)
+
+    def set_visibility(self, visible: bool) -> None:
+        raise NotImplementedError('Use `activate()`, `deactivate()` or `cancel()`. See #3670 for more information.')