diff --git a/lib/src/polyfills.ts b/lib/src/polyfills.ts
index b46d37b..3a0a995 100644
--- a/lib/src/polyfills.ts
+++ b/lib/src/polyfills.ts
@@ -2,3 +2,6 @@ import 'core-js/es/array/find';
 import 'core-js/es/object/assign';
 import 'core-js/es/object/entries';
 import 'core-js/es/object/get-own-property-descriptors';
+import 'core-js/es/map';
+import 'core-js/es/set';
+import 'core-js/es/symbol';
diff --git a/lib/src/sentry.ts b/lib/src/sentry.ts
index 42c353c..255b4bd 100644
--- a/lib/src/sentry.ts
+++ b/lib/src/sentry.ts
@@ -24,7 +24,7 @@ export function initSentry(
 
   const client = new Sentry.BrowserClient({
     dsn: SENTRY_DSN,
-    transport: Sentry.makeFetchTransport,
+    transport: window.fetch ? Sentry.makeFetchTransport : Sentry.makeXHRTransport,
     stackParser: Sentry.defaultStackParser,
     integrations: [
       new Sentry.Breadcrumbs(),