diff --git a/src/main.tsx b/src/main.tsx
index 1619030..2b9b765 100644
--- a/src/main.tsx
+++ b/src/main.tsx
@@ -27,6 +27,16 @@ import { getCachedFullscreenEnabled, isTelegramMobile } from './hooks/useTelegra
 import './i18n';
 import './styles/globals.css';
 
+// Polyfill Object.hasOwn for older iOS/Android WebViews (Safari < 15.4, old Chrome).
+// @telegram-apps/sdk v3 depends on valibot which uses Object.hasOwn internally.
+// Without this, init() throws LaunchParamsRetrieveError on affected devices.
+// See: https://github.com/Telegram-Mini-Apps/tma.js/issues/683
+if (typeof (Object as { hasOwn?: unknown }).hasOwn !== 'function') {
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  (Object as any).hasOwn = (obj: object, prop: PropertyKey): boolean =>
+    Object.prototype.hasOwnProperty.call(obj, prop);
+}
+
 // Only initialize Telegram SDK when running inside Telegram
 const isTelegramEnv =
   !!(window as unknown as Record<string, unknown>).TelegramWebviewProxy ||