diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/util/BackgroundDetectionObserver.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/util/BackgroundDetectionObserver.kt
index 7cc00d023f..a12587ac56 100644
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/util/BackgroundDetectionObserver.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/util/BackgroundDetectionObserver.kt
@@ -29,7 +29,7 @@ import javax.inject.Inject
 @MatrixScope
 internal class BackgroundDetectionObserver @Inject constructor() : LifecycleObserver {
 
-    var isInBackground: Boolean = false
+    var isInBackground: Boolean = true
         private set
 
     private
diff --git a/vector/src/fdroid/AndroidManifest.xml b/vector/src/fdroid/AndroidManifest.xml
index 3a7c107138..022b08f16d 100644
--- a/vector/src/fdroid/AndroidManifest.xml
+++ b/vector/src/fdroid/AndroidManifest.xml
@@ -1,9 +1,11 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
     package="im.vector.app">
 
     <uses-permission android:name="android.permission.WAKE_LOCK" />
     <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
+    <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
     <!--
     Required for long polling account synchronisation in background.
     If not present ACTION_REQUEST_IGNORE_BATTERY_OPTIMIZATIONS intent action won't work
@@ -24,6 +26,11 @@
             android:enabled="true"
             android:exported="false" />
 
+        <service
+            android:name=".fdroid.service.GuardService"
+            android:exported="false"
+            tools:ignore="Instantiatable" />
+
     </application>
 
 </manifest>
\ No newline at end of file
diff --git a/vector/src/fdroid/java/im/vector/app/fdroid/BackgroundSyncStarter.kt b/vector/src/fdroid/java/im/vector/app/fdroid/BackgroundSyncStarter.kt
index 46762f8be7..1e2ed58a17 100644
--- a/vector/src/fdroid/java/im/vector/app/fdroid/BackgroundSyncStarter.kt
+++ b/vector/src/fdroid/java/im/vector/app/fdroid/BackgroundSyncStarter.kt
@@ -19,17 +19,35 @@ package im.vector.app.fdroid
 import android.content.Context
 import im.vector.app.core.di.ActiveSessionHolder
 import im.vector.app.fdroid.receiver.AlarmSyncBroadcastReceiver
+import im.vector.app.fdroid.service.GuardService
 import im.vector.app.features.settings.BackgroundSyncMode
 import im.vector.app.features.settings.VectorPreferences
 import timber.log.Timber
+import android.content.Intent
+import androidx.core.content.ContextCompat
+import org.matrix.android.sdk.internal.session.sync.job.SyncService
 
 object BackgroundSyncStarter {
     fun start(context: Context, vectorPreferences: VectorPreferences, activeSessionHolder: ActiveSessionHolder) {
         if (vectorPreferences.areNotificationEnabledForDevice()) {
             val activeSession = activeSessionHolder.getSafeActiveSession() ?: return
 
+            val intent = Intent(context, GuardService::class.java)
+            if (vectorPreferences.getFdroidSyncBackgroundMode() == BackgroundSyncMode.FDROID_BACKGROUND_SYNC_MODE_FOR_REALTIME) {
+                intent.putExtra(SyncService.EXTRA_SESSION_ID, activeSession.sessionId)
+            } else {
+                intent.putExtra(SyncService.EXTRA_SESSION_ID, "") // this assures the GuardService runs, but will not start VectorSyncService
+            }
+            intent.putExtra(SyncService.EXTRA_DELAY_SECONDS, vectorPreferences.backgroundSyncDelay())
+            try {
+                Timber.i("## Sync: starting GuardService")
+                ContextCompat.startForegroundService(context, intent)
+            } catch (ex: Throwable) {
+                Timber.e("## Sync: ERROR starting GuardService")
+            }
+
             when (vectorPreferences.getFdroidSyncBackgroundMode()) {
-                BackgroundSyncMode.FDROID_BACKGROUND_SYNC_MODE_FOR_BATTERY -> {
+                BackgroundSyncMode.FDROID_BACKGROUND_SYNC_MODE_FOR_BATTERY  -> {
                     // we rely on periodic worker
                     Timber.i("## Sync: Work scheduled to periodically sync in ${vectorPreferences.backgroundSyncDelay()}s")
                     activeSession.startAutomaticBackgroundSync(
@@ -43,7 +61,7 @@ object BackgroundSyncStarter {
                     AlarmSyncBroadcastReceiver.scheduleAlarm(context, activeSession.sessionId, vectorPreferences.backgroundSyncDelay())
                     Timber.i("## Sync: Alarm scheduled to start syncing")
                 }
-                BackgroundSyncMode.FDROID_BACKGROUND_SYNC_MODE_DISABLED -> {
+                BackgroundSyncMode.FDROID_BACKGROUND_SYNC_MODE_DISABLED     -> {
                     // we do nothing
                     Timber.i("## Sync: background sync is disabled")
                 }
diff --git a/vector/src/fdroid/java/im/vector/app/fdroid/service/GuardService.kt b/vector/src/fdroid/java/im/vector/app/fdroid/service/GuardService.kt
new file mode 100644
index 0000000000..6fa2f1f357
--- /dev/null
+++ b/vector/src/fdroid/java/im/vector/app/fdroid/service/GuardService.kt
@@ -0,0 +1,156 @@
+/*
+ * Copyright (c) 2021 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package im.vector.app.fdroid.service
+
+import android.app.Service
+import android.content.Intent
+import android.os.IBinder
+import androidx.core.content.getSystemService
+import timber.log.Timber
+import im.vector.app.R
+import im.vector.app.core.extensions.vectorComponent
+import im.vector.app.features.notifications.NotificationUtils
+import java.util.Timer
+import java.util.TimerTask
+import im.vector.app.core.services.VectorSyncService
+import androidx.core.content.ContextCompat
+import org.matrix.android.sdk.internal.session.sync.job.SyncService
+import android.app.AlarmManager
+import android.os.Build
+import android.app.PendingIntent
+import im.vector.app.features.settings.BackgroundSyncMode
+
+/**
+ */
+class GuardService : Service() {
+
+    private var timer = Timer()
+    private var sessionId: String? = null
+    private var running: Boolean = false
+
+    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
+        Timber.i("## Sync: onStartCommand GuardService running:$running")
+        if (running) {
+            if (intent != null) {
+                val liveLine = intent.getBooleanExtra(EXTRA_LIFELINE, false)
+                if (liveLine) {//called from lifeLine?
+                    scheduleLifeLine()
+                    return START_STICKY
+                }
+            }
+        }
+        try {
+            timer.cancel()
+        } catch (ex: Exception) {
+        }
+        val notificationSubtitleRes = R.string.notification_listening_for_events
+        val notification = notificationUtils.buildForegroundServiceNotification(notificationSubtitleRes, false)
+        startForeground(NotificationUtils.NOTIFICATION_ID_FOREGROUND_SERVICE + 1, notification)
+        try {
+            val sharedPref = getSharedPreferences(PREF_NAME_SESSION_ID, 0)
+            var delayInSeconds = BackgroundSyncMode.DEFAULT_SYNC_DELAY_SECONDS
+            if (intent != null) {
+                sessionId = intent.getStringExtra(SyncService.EXTRA_SESSION_ID)
+                delayInSeconds = intent.getIntExtra(SyncService.EXTRA_DELAY_SECONDS, BackgroundSyncMode.DEFAULT_SYNC_DELAY_SECONDS)
+                val liveLine = intent.getBooleanExtra(EXTRA_LIFELINE, false)
+                if (liveLine) {
+                    Timber.i("## Sync: GuardService restarted by liveLine")
+                }
+                if (sessionId.isNullOrEmpty()) {
+                    Timber.i("## Sync: GuardService getting sessionId from sharedPreferences")
+                    sessionId = sharedPref.getString(PREF_NAME_SESSION_ID, null)
+                } else {
+                    Timber.i("## Sync: GuardService saving sessionId to sharedPreferences")
+                    val editor = sharedPref.edit()
+                    editor.putString(PREF_NAME_SESSION_ID, sessionId)
+                    editor.apply()
+                }
+            } else {
+                Timber.i("## Sync: GuardService intent is null in GuardService, getting sessionId from sharedPreferences")
+                sessionId = sharedPref.getString(PREF_NAME_SESSION_ID, null)
+            }
+            timer = Timer()
+            timer.scheduleAtFixedRate(object : TimerTask() {
+                override fun run() {
+                    if (sessionId.isNullOrEmpty()) {
+                        Timber.i("## Sync: timer still alive GuardService sessionId:nullOrEmpty")
+                    } else {
+                        Timber.i("## Sync: timer still alive GuardService sessionId:${sessionId}")
+                        try {
+                            val syncIntent = Intent(applicationContext, VectorSyncService::class.java)
+                            syncIntent.putExtra(SyncService.EXTRA_SESSION_ID, sessionId)
+                            syncIntent.putExtra(SyncService.EXTRA_PERIODIC, true)
+                            ContextCompat.startForegroundService(applicationContext, syncIntent)
+                        } catch (ex: Throwable) {
+                        }
+                    }
+                }
+            }, delayInSeconds * 1000L, delayInSeconds * 1000L)
+        } catch (ex: Exception) {
+            Timber.e("## Sync: error in GuardService when creating timer")
+        }
+        if (!running) {
+            scheduleLifeLine()
+        }
+        running = true
+        return START_STICKY
+    }
+
+    private lateinit var notificationUtils: NotificationUtils
+
+    override fun onCreate() {
+        Timber.i("## Sync: onCreate GuardService")
+        super.onCreate()
+        notificationUtils = vectorComponent().notificationUtils()
+    }
+
+    override fun onDestroy() {
+        Timber.i("## Sync: onDestroy GuardService")
+        try {
+            timer.cancel()
+        } catch (ex: Exception) {
+        }
+        super.onDestroy()
+    }
+
+    override fun onBind(intent: Intent?): IBinder? {
+        return null
+    }
+
+    private fun scheduleLifeLine() {
+        Timber.d("## Sync: GuardService scheduleLifeLine")
+        val intent = Intent(applicationContext, GuardService::class.java)
+        intent.putExtra(EXTRA_LIFELINE, true)
+
+        val pendingIntent = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+            PendingIntent.getForegroundService(this, 0, intent, 0)
+        } else {
+            PendingIntent.getService(this, 0, intent, 0)
+        }
+        val firstMillis = System.currentTimeMillis() + 60 * 1000L
+        val alarmMgr = getSystemService<AlarmManager>()!!
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+            alarmMgr.setAndAllowWhileIdle(AlarmManager.RTC_WAKEUP, firstMillis, pendingIntent)
+        } else {
+            alarmMgr.set(AlarmManager.RTC_WAKEUP, firstMillis, pendingIntent)
+        }
+    }
+
+    companion object {
+        const val PREF_NAME_SESSION_ID = "GuardServiceLastActiveSessionId"
+        const val EXTRA_LIFELINE = "GuardServiceLifeLine"
+    }
+}