diff --git a/mobile/android/app/src/main/AndroidManifest.xml b/mobile/android/app/src/main/AndroidManifest.xml
index 0b28c46f51..470c9ff90e 100644
--- a/mobile/android/app/src/main/AndroidManifest.xml
+++ b/mobile/android/app/src/main/AndroidManifest.xml
@@ -53,6 +53,9 @@
                 android:name="flutter_deeplinking_enabled"
                 android:value="false" />
         </activity>
+        <receiver
+            android:name=".AgentLiveUpdateExpiryReceiver"
+            android:exported="false" />
         <!-- Don't delete the meta-data below.
              This is used by the Flutter tool to generate GeneratedPluginRegistrant.java -->
         <meta-data
diff --git a/mobile/android/app/src/main/kotlin/xyz/block/buzz/mobile/AgentLiveUpdateManager.kt b/mobile/android/app/src/main/kotlin/xyz/block/buzz/mobile/AgentLiveUpdateManager.kt
index 1f6a2eb9fb..aec3490aad 100644
--- a/mobile/android/app/src/main/kotlin/xyz/block/buzz/mobile/AgentLiveUpdateManager.kt
+++ b/mobile/android/app/src/main/kotlin/xyz/block/buzz/mobile/AgentLiveUpdateManager.kt
@@ -2,21 +2,37 @@ package xyz.block.buzz.mobile
 
 import android.Manifest
 import android.app.Activity
+import android.app.AlarmManager
 import android.app.Notification
 import android.app.NotificationChannel
 import android.app.NotificationManager
 import android.app.PendingIntent
+import android.content.BroadcastReceiver
+import android.content.Context
 import android.content.Intent
 import android.content.pm.PackageManager
 import android.net.Uri
 import android.os.Build
 import android.os.Bundle
 
+private const val CHANNEL_ID = "buzz_agent_live_updates"
+private const val NOTIFICATION_TAG = "buzz_agent_live_update"
+private const val NOTIFICATION_ID = 24_200
+private const val NOTIFICATION_PERMISSION_REQUEST_CODE = 24_201
+private const val CONTENT_INTENT_REQUEST_CODE = 24_202
+private const val EXPIRY_INTENT_REQUEST_CODE = 24_203
+private const val EXPIRY_INTENT_ACTION = "xyz.block.buzz.mobile.AGENT_LIVE_UPDATE_EXPIRED"
+private const val PREFERENCES_NAME = "buzz_agent_live_updates"
+private const val PERMISSION_REQUESTED_KEY = "notification_permission_requested"
+private const val REQUEST_PROMOTED_ONGOING_EXTRA = "android.requestPromotedOngoing"
+
 internal class AgentLiveUpdateManager(
     private val activity: Activity,
 ) {
     private val notificationManager =
         activity.getSystemService(NotificationManager::class.java)
+    private val alarmManager =
+        activity.getSystemService(AlarmManager::class.java)
     private val preferences =
         activity.getSharedPreferences(PREFERENCES_NAME, Activity.MODE_PRIVATE)
 
@@ -37,6 +53,7 @@ internal class AgentLiveUpdateManager(
 
     fun dismiss() {
         pendingPayload = null
+        cancelLegacyExpiry()
         notificationManager.cancel(NOTIFICATION_TAG, NOTIFICATION_ID)
     }
 
@@ -125,6 +142,7 @@ internal class AgentLiveUpdateManager(
             .build()
 
         notificationManager.notify(NOTIFICATION_TAG, NOTIFICATION_ID, notification)
+        scheduleLegacyExpiry(payload.expiresAtMillis)
     }
 
     private fun newNotificationBuilder(): Notification.Builder =
@@ -151,6 +169,34 @@ internal class AgentLiveUpdateManager(
         notificationManager.createNotificationChannel(channel)
     }
 
+    private fun scheduleLegacyExpiry(expiresAtMillis: Long) {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+            cancelLegacyExpiry()
+            return
+        }
+        alarmManager.setExactAndAllowWhileIdle(
+            AlarmManager.RTC_WAKEUP,
+            legacyExpiryTriggerAt(expiresAtMillis, System.currentTimeMillis()),
+            expiryIntent(),
+        )
+    }
+
+    private fun cancelLegacyExpiry() {
+        val intent = expiryIntent()
+        alarmManager.cancel(intent)
+        intent.cancel()
+    }
+
+    private fun expiryIntent(): PendingIntent =
+        PendingIntent.getBroadcast(
+            activity,
+            EXPIRY_INTENT_REQUEST_CODE,
+            Intent(activity, AgentLiveUpdateExpiryReceiver::class.java).apply {
+                action = EXPIRY_INTENT_ACTION
+            },
+            PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE,
+        )
+
     private fun contentIntent(payload: AgentLiveUpdatePayload): PendingIntent {
         val messageId = payload.messageId
         val intent = if (messageId != null) {
@@ -176,15 +222,21 @@ internal class AgentLiveUpdateManager(
             PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE,
         )
     }
+}
 
-    companion object {
-        private const val CHANNEL_ID = "buzz_agent_live_updates"
-        private const val NOTIFICATION_TAG = "buzz_agent_live_update"
-        private const val NOTIFICATION_ID = 24_200
-        private const val NOTIFICATION_PERMISSION_REQUEST_CODE = 24_201
-        private const val CONTENT_INTENT_REQUEST_CODE = 24_202
-        private const val PREFERENCES_NAME = "buzz_agent_live_updates"
-        private const val PERMISSION_REQUESTED_KEY = "notification_permission_requested"
-        private const val REQUEST_PROMOTED_ONGOING_EXTRA = "android.requestPromotedOngoing"
+internal fun legacyExpiryTriggerAt(
+    expiresAtMillis: Long,
+    nowMillis: Long,
+): Long = expiresAtMillis.coerceAtLeast(nowMillis + 1L)
+
+internal class AgentLiveUpdateExpiryReceiver : BroadcastReceiver() {
+    override fun onReceive(
+        context: Context,
+        intent: Intent,
+    ) {
+        if (intent.action != EXPIRY_INTENT_ACTION) return
+        context
+            .getSystemService(NotificationManager::class.java)
+            .cancel(NOTIFICATION_TAG, NOTIFICATION_ID)
     }
 }
diff --git a/mobile/android/app/src/test/kotlin/xyz/block/buzz/mobile/AgentLiveUpdatePayloadTest.kt b/mobile/android/app/src/test/kotlin/xyz/block/buzz/mobile/AgentLiveUpdatePayloadTest.kt
index 9da9fbcba3..bf360742e2 100644
--- a/mobile/android/app/src/test/kotlin/xyz/block/buzz/mobile/AgentLiveUpdatePayloadTest.kt
+++ b/mobile/android/app/src/test/kotlin/xyz/block/buzz/mobile/AgentLiveUpdatePayloadTest.kt
@@ -5,6 +5,16 @@ import kotlin.test.assertEquals
 import kotlin.test.assertNull
 
 class AgentLiveUpdatePayloadTest {
+    @Test
+    fun legacyExpiryTriggerUsesPayloadDeadlineWhenStillFuture() {
+        assertEquals(2_000L, legacyExpiryTriggerAt(2_000L, 1_000L))
+    }
+
+    @Test
+    fun legacyExpiryTriggerSchedulesImmediateCancellationWhenAlreadyExpired() {
+        assertEquals(1_001L, legacyExpiryTriggerAt(500L, 1_000L))
+    }
+
     @Test
     fun `parses Flutter method channel values`() {
         val payload = AgentLiveUpdatePayload.from(
diff --git a/mobile/lib/features/channels/agent_activity/observer_subscription.dart b/mobile/lib/features/channels/agent_activity/observer_subscription.dart
index 62bb66d252..f9ac961b99 100644
--- a/mobile/lib/features/channels/agent_activity/observer_subscription.dart
+++ b/mobile/lib/features/channels/agent_activity/observer_subscription.dart
@@ -12,6 +12,7 @@ import 'transcript_builder.dart';
 /// Maximum observer events to keep per agent.
 const _maxObserverEvents = 800;
 const _observerReplayLimit = 200;
+const _observerReplayWindow = Duration(hours: 24, minutes: 1);
 
 /// Key for channel-scoped transcript reads.
 typedef ObserverKey = ({String channelId, String agentPubkey});
@@ -134,6 +135,7 @@ class ObserverRelayNotifier extends Notifier<ObserverRelayState> {
       final session = ref.read(relaySessionProvider.notifier);
       final replayBoundary =
           DateTime.now().toUtc().millisecondsSinceEpoch ~/ 1000;
+      final replaySince = replayBoundary - _observerReplayWindow.inSeconds;
       final filterTags = {
         '#p': [ownerPubkey],
       };
@@ -144,6 +146,7 @@ class ObserverRelayNotifier extends Notifier<ObserverRelayState> {
             kinds: [EventKind.agentObserverFrame],
             tags: filterTags,
             limit: _observerReplayLimit,
+            since: replaySince,
             until: replayBoundary,
           ),
         );
@@ -271,9 +274,12 @@ class ObserverRelayNotifier extends Notifier<ObserverRelayState> {
       );
       final plaintext = nip44Decrypt(conversationKey, event.content);
       final json = jsonDecode(plaintext) as Map<String, dynamic>;
+      final receivedAt = isHistorical
+          ? _historicalFrameTime(event)
+          : DateTime.now().toUtc();
       return ObserverFrame.fromJson(
         json,
-        receivedAt: DateTime.now().toUtc(),
+        receivedAt: receivedAt,
         isHistorical: isHistorical,
       );
     } catch (error) {
@@ -283,6 +289,18 @@ class ObserverRelayNotifier extends Notifier<ObserverRelayState> {
     }
   }
 
+  DateTime _historicalFrameTime(NostrEvent event) {
+    final now = DateTime.now().toUtc();
+    final eventAt = DateTime.fromMillisecondsSinceEpoch(
+      event.createdAt * Duration.millisecondsPerSecond,
+      isUtc: true,
+    );
+    // Historical frames were not received now. Preserve their signed event age
+    // so replay cannot make an old, unterminated turn look newly active. Clamp
+    // future-dated events to now so host clock skew cannot extend freshness.
+    return eventAt.isAfter(now) ? now : eventAt;
+  }
+
   void _emit({required ObserverConnectionState connection}) {
     if (_disposed) return;
     state = ObserverRelayState(
diff --git a/mobile/lib/shared/notifications/agent_live_update_preferences.dart b/mobile/lib/shared/notifications/agent_live_update_preferences.dart
index 0f5a3bb547..e440f31cc3 100644
--- a/mobile/lib/shared/notifications/agent_live_update_preferences.dart
+++ b/mobile/lib/shared/notifications/agent_live_update_preferences.dart
@@ -13,6 +13,7 @@ class AgentLiveUpdatesEnabledNotifier extends Notifier<bool> {
   bool build() =>
       ref.read(savedPrefsProvider).getBool(_agentLiveUpdatesEnabledKey) ?? true;
 
+  /// Persists whether agent Live Updates should be shown on this device.
   void setEnabled(bool enabled) {
     state = enabled;
     ref.read(savedPrefsProvider).setBool(_agentLiveUpdatesEnabledKey, enabled);
diff --git a/mobile/test/features/channels/agent_activity/observer_subscription_test.dart b/mobile/test/features/channels/agent_activity/observer_subscription_test.dart
index 9b27152b65..0d1d050ddb 100644
--- a/mobile/test/features/channels/agent_activity/observer_subscription_test.dart
+++ b/mobile/test/features/channels/agent_activity/observer_subscription_test.dart
@@ -148,6 +148,10 @@ void main() {
       expect(historyFilter.limit, 200);
       expect(historyFilter.tags['#p'], contains(myPubkey));
       expect(historyFilter.until, filter.since);
+      expect(
+        historyFilter.until! - historyFilter.since!,
+        const Duration(hours: 24, minutes: 1).inSeconds,
+      );
     },
   );
 
@@ -312,6 +316,59 @@ void main() {
     expect((state.transcript.single as LifecycleItem).title, 'Turn started');
   });
 
+  test('preserves replay age so stale turns do not restart', () async {
+    final ownerKeychain = nostr.Keys.generate();
+    final agentKeychain = nostr.Keys.generate();
+    final nowSeconds =
+        DateTime.now().toUtc().millisecondsSinceEpoch ~/
+        Duration.millisecondsPerSecond;
+    final eventCreatedAt = nowSeconds - 120;
+    final relaySession = _RecordingRelaySession()
+      ..historyEvents = [
+        _observerEvent(
+          ownerKeychain: ownerKeychain,
+          agentKeychain: agentKeychain,
+          channelId: 'test-channel',
+          seq: 1,
+          createdAt: eventCreatedAt,
+        ),
+      ];
+    final container = ProviderContainer(
+      overrides: [
+        relaySessionProvider.overrideWith(() => relaySession),
+        relayConfigProvider.overrideWith(
+          () => _FakeRelayConfigNotifier(nsec: ownerKeychain.nsec),
+        ),
+      ],
+    );
+    addTearDown(container.dispose);
+
+    const channelId = 'test-channel';
+    final key = (channelId: channelId, agentPubkey: agentKeychain.public);
+    container.read(observerSubscriptionProvider(key));
+    await Future<void>.delayed(Duration.zero);
+
+    final relayState = container.read(observerRelayProvider);
+    final replayFrame = relayState.framesByAgent[agentKeychain.public]!.single;
+    expect(
+      replayFrame.receivedAt,
+      DateTime.fromMillisecondsSinceEpoch(
+        eventCreatedAt * Duration.millisecondsPerSecond,
+        isUtc: true,
+      ),
+    );
+    expect(
+      reduceActiveAgentTurns(
+        relayState.framesByAgent,
+        now: DateTime.fromMillisecondsSinceEpoch(
+          nowSeconds * Duration.millisecondsPerSecond,
+          isUtc: true,
+        ),
+      ),
+      isEmpty,
+    );
+  });
+
   test(
     'decrypts observer frames and exposes channel-scoped transcript',
     () async {
@@ -459,6 +516,7 @@ NostrEvent _observerEvent({
   required nostr.Keys agentKeychain,
   required String channelId,
   required int seq,
+  int? createdAt,
 }) {
   final conversationKey = getConversationKey(
     agentKeychain.secret,
@@ -485,7 +543,17 @@ NostrEvent _observerEvent({
     secretKey: agentKeychain.secret,
     verify: false,
   );
-  return NostrEvent.fromJson(event.toMap());
+  final signedEvent = NostrEvent.fromJson(event.toMap());
+  if (createdAt == null) return signedEvent;
+  return NostrEvent(
+    id: signedEvent.id,
+    pubkey: signedEvent.pubkey,
+    createdAt: createdAt,
+    kind: signedEvent.kind,
+    tags: signedEvent.tags,
+    content: signedEvent.content,
+    sig: signedEvent.sig,
+  );
 }
 
 class _FakeRelayConfigNotifier extends RelayConfigNotifier {