diff --git a/.swift-version b/.swift-version
new file mode 100644
index 0000000..31b44b0
--- /dev/null
+++ b/.swift-version
@@ -0,0 +1 @@
+6.2.4
\ No newline at end of file
diff --git a/lib/services/message_retry_service.dart b/lib/services/message_retry_service.dart
index df81d16..56d7b82 100644
--- a/lib/services/message_retry_service.dart
+++ b/lib/services/message_retry_service.dart
@@ -355,24 +355,12 @@ class MessageRetryService extends ChangeNotifier {
         'Hash-based match failed for $ackHashHex, falling back to queue-based matching',
       );
 
-      // Try to identify the correct contact from _activeMessages first.
-      String? targetContactKey;
-      for (final activeId in _activeMessages) {
-        final activeContact = _pendingContacts[activeId];
-        if (activeContact != null) {
-          targetContactKey = activeContact.publicKeyHex;
-          break;
-        }
-      }
-
-      final queuesToSearch = targetContactKey != null
-          ? {targetContactKey: _pendingMessageQueuePerContact[targetContactKey]}
-          : _pendingMessageQueuePerContact;
+      // Search all contact queues so concurrent chats don't miss matches.
+      final queuesToSearch = _pendingMessageQueuePerContact;
 
       for (var entry in queuesToSearch.entries) {
         final contactKey = entry.key;
         final queue = entry.value;
-        if (queue == null) continue;
 
         // Drain stale entries until we find a valid one or exhaust the queue.
         while (queue.isNotEmpty) {
diff --git a/lib/services/notification_service.dart b/lib/services/notification_service.dart
index 4ed59d0..62d3796 100644
--- a/lib/services/notification_service.dart
+++ b/lib/services/notification_service.dart
@@ -232,7 +232,9 @@ class NotificationService {
 
     try {
       await _notifications.show(
-        id: contactId?.hashCode ?? DateTime.now().millisecondsSinceEpoch,
+        id: contactId != null
+            ? 'advert:$contactId'.hashCode
+            : DateTime.now().millisecondsSinceEpoch,
         title: _l10n.notification_newTypeDiscovered(contactType),
         body: contactName,
         notificationDetails: notificationDetails,
@@ -355,7 +357,7 @@ class NotificationService {
   Future<void> clearAdvertNotifications(List<String> contactIds) async {
     if (!await _ensureInitialized()) return;
     for (final id in contactIds) {
-      await _notifications.cancel(id: id.hashCode);
+      await _notifications.cancel(id: 'advert:$id'.hashCode);
     }
   }