diff --git a/lib/src/utils/room_key_request.dart b/lib/src/utils/room_key_request.dart
index 4e99ef0..b2cd9a0 100644
--- a/lib/src/utils/room_key_request.dart
+++ b/lib/src/utils/room_key_request.dart
@@ -24,7 +24,8 @@ class RoomKeyRequest extends ToDeviceEvent {
     await requestingDevice.setVerified(true, client);
     var message = session.content;
     message['forwarding_curve25519_key_chain'] = forwardedKeys;
-    message['session_key'] = session.inboundGroupSession.export_session(0);
+    
+    message['session_key'] = session.inboundGroupSession.export_session(session.inboundGroupSession.first_known_index());
     await client.sendToDevice(
       [requestingDevice],
       'm.forwarded_room_key',
diff --git a/pubspec.lock b/pubspec.lock
index bbc0327..2e5d5f1 100644
--- a/pubspec.lock
+++ b/pubspec.lock
@@ -333,7 +333,7 @@ packages:
       name: pedantic
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.8.0+1"
+    version: "1.9.0"
   pointycastle:
     dependency: transitive
     description: