diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index 81d0586..e8ed1be 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -11,8 +11,6 @@
     <uses-permission android:name="android.permission.AUTHENTICATE_ACCOUNTS" />
     <uses-permission android:name="android.permission.READ_SYNC_SETTINGS" />
     <uses-permission android:name="android.permission.WRITE_SYNC_SETTINGS" />
-    <uses-permission android:name="android.permission.READ_CONTACTS" />
-    <uses-permission android:name="android.permission.WRITE_CONTACTS" />
 
     <application
         android:name="android.support.multidex.MultiDexApplication"
@@ -120,20 +118,10 @@
             </intent-filter>
         </activity>
 
-        <service
-            android:name=".service.BitmessageService"
-            android:exported="false" />
         <service
             android:name=".service.ProofOfWorkService"
             android:exported="false" />
 
-        <!-- Synchronization -->
-        <provider
-            android:name=".synchronization.StubProvider"
-            android:authorities="ch.dissem.apps.abit.provider"
-            android:exported="false"
-            android:syncable="true" />
-
         <!-- Exports -->
         <provider
             android:name="android.support.v4.content.FileProvider"
@@ -145,30 +133,6 @@
                 android:resource="@xml/file_paths" />
         </provider>
 
-        <service
-            android:name=".synchronization.AuthenticatorService"
-            android:exported="true"
-            tools:ignore="ExportedService">
-            <intent-filter>
-                <action android:name="android.accounts.AccountAuthenticator" />
-            </intent-filter>
-
-            <meta-data
-                android:name="android.accounts.AccountAuthenticator"
-                android:resource="@xml/authenticator" />
-        </service>
-        <service
-            android:name=".synchronization.SyncService"
-            android:exported="true"
-            tools:ignore="ExportedService">
-            <intent-filter>
-                <action android:name="android.content.SyncAdapter" />
-            </intent-filter>
-
-            <meta-data
-                android:name="android.content.SyncAdapter"
-                android:resource="@xml/syncadapter" />
-        </service>
         <service
             android:name=".service.BitmessageIntentService"
             android:exported="false" />
@@ -182,7 +146,12 @@
         </receiver>
 
         <service
-            android:name=".service.StartupNodeOnWifiService"
+            android:name=".service.NodeStartupService"
+            android:exported="true"
+            android:permission="android.permission.BIND_JOB_SERVICE" />
+
+        <service
+            android:name=".service.CleanupService"
             android:exported="true"
             android:permission="android.permission.BIND_JOB_SERVICE" />
 
diff --git a/app/src/main/java/ch/dissem/apps/abit/ComposeMessageFragment.kt b/app/src/main/java/ch/dissem/apps/abit/ComposeMessageFragment.kt
index 10cb977..bca4f5f 100644
--- a/app/src/main/java/ch/dissem/apps/abit/ComposeMessageFragment.kt
+++ b/app/src/main/java/ch/dissem/apps/abit/ComposeMessageFragment.kt
@@ -35,7 +35,7 @@ import ch.dissem.apps.abit.ComposeMessageActivity.Companion.EXTRA_SUBJECT
 import ch.dissem.apps.abit.adapter.ContactAdapter
 import ch.dissem.apps.abit.dialog.SelectEncodingDialogFragment
 import ch.dissem.apps.abit.service.Singleton
-import ch.dissem.apps.abit.util.Preferences
+import ch.dissem.apps.abit.util.preferences
 import ch.dissem.bitmessage.entity.BitmessageAddress
 import ch.dissem.bitmessage.entity.Plaintext
 import ch.dissem.bitmessage.entity.Plaintext.Type.BROADCAST
@@ -76,7 +76,7 @@ class ComposeMessageFragment : Fragment() {
                 parents.addAll(draft.parents)
             } else {
                 var id = getSerializable(EXTRA_IDENTITY) as? BitmessageAddress
-                if (context != null && (id == null || id.privateKey == null)) {
+                if (context != null && id?.privateKey == null) {
                     id = Singleton.getIdentity(context!!)
                 }
                 if (id?.privateKey != null) {
@@ -94,8 +94,7 @@ class ComposeMessageFragment : Fragment() {
                 if (containsKey(EXTRA_CONTENT)) {
                     content = getString(EXTRA_CONTENT)
                 }
-                encoding = getSerializable(EXTRA_ENCODING) as? Plaintext.Encoding ?:
-                    Plaintext.Encoding.SIMPLE
+                encoding = getSerializable(EXTRA_ENCODING) as? Plaintext.Encoding ?: Plaintext.Encoding.SIMPLE
 
                 if (containsKey(EXTRA_PARENT)) {
                     val parent = getSerializable(EXTRA_PARENT) as Plaintext
@@ -221,7 +220,7 @@ class ComposeMessageFragment : Fragment() {
         }
         val sender = sender_input.selectedItem as? ch.dissem.bitmessage.entity.BitmessageAddress
         sender?.let { builder.from(it) }
-        if (!Preferences.requestAcknowledgements(ctx)) {
+        if (!ctx.preferences.requestAcknowledgements) {
             builder.preventAck()
         }
         when (encoding) {
diff --git a/app/src/main/java/ch/dissem/apps/abit/MainActivity.kt b/app/src/main/java/ch/dissem/apps/abit/MainActivity.kt
index ade79e1..516e7bb 100644
--- a/app/src/main/java/ch/dissem/apps/abit/MainActivity.kt
+++ b/app/src/main/java/ch/dissem/apps/abit/MainActivity.kt
@@ -31,11 +31,7 @@ import ch.dissem.apps.abit.listener.ListSelectionListener
 import ch.dissem.apps.abit.repository.AndroidLabelRepository.Companion.LABEL_ARCHIVE
 import ch.dissem.apps.abit.service.Singleton
 import ch.dissem.apps.abit.service.Singleton.currentLabel
-import ch.dissem.apps.abit.synchronization.SyncAdapter
-import ch.dissem.apps.abit.util.NetworkUtils
-import ch.dissem.apps.abit.util.Preferences
-import ch.dissem.apps.abit.util.getColor
-import ch.dissem.apps.abit.util.getIcon
+import ch.dissem.apps.abit.util.*
 import ch.dissem.bitmessage.BitmessageContext
 import ch.dissem.bitmessage.entity.BitmessageAddress
 import ch.dissem.bitmessage.entity.Conversation
@@ -145,11 +141,6 @@ class MainActivity : AppCompatActivity(), ListSelectionListener<Serializable> {
             ComposeMessageActivity.launchReplyTo(this, item)
         }
 
-        if (Preferences.useTrustedNode(this)) {
-            SyncAdapter.startSync(this)
-        } else {
-            SyncAdapter.stopSync(this)
-        }
         if (drawer.isDrawerOpen) {
             MaterialShowcaseView.Builder(this)
                 .setMaskColour(R.color.colorPrimary)
@@ -179,8 +170,6 @@ class MainActivity : AppCompatActivity(), ListSelectionListener<Serializable> {
                 .setDelay(1000)
                 .show()
         }
-
-        SyncAdapter.startSync(this)
     }
 
     private fun <F> changeList(listFragment: F) where F : Fragment, F : ListHolder<*> {
@@ -259,14 +248,13 @@ class MainActivity : AppCompatActivity(), ListSelectionListener<Serializable> {
 
         nodeSwitch = SwitchDrawerItem()
             .withIdentifier(ID_NODE_SWITCH)
-            .withName(R.string.full_node)
+            .withName(R.string.online)
             .withIcon(CommunityMaterial.Icon.cmd_cloud_outline)
-            .withChecked(Preferences.isFullNodeActive(this))
+            .withChecked(preferences.online)
             .withOnCheckedChangeListener { _, _, isChecked ->
+                preferences.online = isChecked
                 if (isChecked) {
-                    NetworkUtils.enableNode(this@MainActivity)
-                } else {
-                    NetworkUtils.disableNode(this@MainActivity)
+                    network.enableNode(true)
                 }
             }
 
@@ -369,10 +357,8 @@ class MainActivity : AppCompatActivity(), ListSelectionListener<Serializable> {
     }
 
     override fun onResume() {
+        network.enableNode(false)
         updateUnread()
-        if (Preferences.isFullNodeActive(this) && Preferences.isConnectionAllowed(this@MainActivity)) {
-            NetworkUtils.enableNode(this, false)
-        }
         Singleton.getMessageListener(this).resetNotification()
         currentLabel.addObserver(this) { label ->
             if (label != null && label.id is Long) {
@@ -578,15 +564,6 @@ class MainActivity : AppCompatActivity(), ListSelectionListener<Serializable> {
 
         private var instance: WeakReference<MainActivity>? = null
 
-        fun updateNodeSwitch() {
-            apply {
-                runOnUiThread {
-                    nodeSwitch.withChecked(Preferences.isFullNodeActive(this))
-                    drawer.updateStickyFooterItem(nodeSwitch)
-                }
-            }
-        }
-
         /**
          * Runs the given code in the main activity context, if it currently exists. Otherwise,
          * it's ignored.
diff --git a/app/src/main/java/ch/dissem/apps/abit/MessageListFragment.kt b/app/src/main/java/ch/dissem/apps/abit/MessageListFragment.kt
index 6597810..dc0b30f 100644
--- a/app/src/main/java/ch/dissem/apps/abit/MessageListFragment.kt
+++ b/app/src/main/java/ch/dissem/apps/abit/MessageListFragment.kt
@@ -134,23 +134,27 @@ class MessageListFragment : Fragment(), ListHolder<Label> {
     }
 
     private fun doUpdateList(label: Label?) {
-        val mainActivity = activity as? MainActivity
-        swipeableMessageAdapter?.clear(label)
-        if (label == null) {
-            mainActivity?.updateTitle(getString(R.string.app_name))
-            swipeableMessageAdapter?.notifyDataSetChanged()
-            return
-        }
-        emptyTrashMenuItem?.isVisible = label.type == Label.Type.TRASH
-        mainActivity?.apply {
-            if ("archive" == label.toString()) {
-                updateTitle(getString(R.string.archive))
-            } else {
-                updateTitle(label.toString())
+        // If the menu item isn't available yet, we should wait - the method will be called again once it's
+        // initialized.
+        emptyTrashMenuItem?.let { menuItem ->
+            val mainActivity = activity as? MainActivity
+            swipeableMessageAdapter?.clear(label)
+            if (label == null) {
+                mainActivity?.updateTitle(getString(R.string.app_name))
+                swipeableMessageAdapter?.notifyDataSetChanged()
+                return
+            }
+            menuItem.isVisible = label.type == Label.Type.TRASH
+            mainActivity?.apply {
+                if ("archive" == label.toString()) {
+                    updateTitle(getString(R.string.archive))
+                } else {
+                    updateTitle(label.toString())
+                }
             }
-        }
 
-        loadMoreItems()
+            loadMoreItems()
+        }
     }
 
     override fun onCreateView(
@@ -296,6 +300,7 @@ class MessageListFragment : Fragment(), ListHolder<Label> {
     override fun onCreateOptionsMenu(menu: Menu, inflater: MenuInflater) {
         inflater.inflate(R.menu.message_list, menu)
         emptyTrashMenuItem = menu.findItem(R.id.empty_trash)
+        currentLabel.value?.let { doUpdateList(it) }
         super.onCreateOptionsMenu(menu, inflater)
     }
 
diff --git a/app/src/main/java/ch/dissem/apps/abit/SettingsFragment.kt b/app/src/main/java/ch/dissem/apps/abit/SettingsFragment.kt
index 7ddc4d7..717a5cd 100644
--- a/app/src/main/java/ch/dissem/apps/abit/SettingsFragment.kt
+++ b/app/src/main/java/ch/dissem/apps/abit/SettingsFragment.kt
@@ -17,7 +17,10 @@
 package ch.dissem.apps.abit
 
 import android.app.Activity
-import android.content.*
+import android.content.ComponentName
+import android.content.Context
+import android.content.Intent
+import android.content.ServiceConnection
 import android.os.Bundle
 import android.os.IBinder
 import android.support.v4.app.Fragment
@@ -33,12 +36,9 @@ import android.widget.Toast
 import ch.dissem.apps.abit.service.BatchProcessorService
 import ch.dissem.apps.abit.service.SimpleJob
 import ch.dissem.apps.abit.service.Singleton
-import ch.dissem.apps.abit.synchronization.SyncAdapter
-import ch.dissem.apps.abit.util.Constants.PREFERENCE_SERVER_POW
-import ch.dissem.apps.abit.util.Constants.PREFERENCE_TRUSTED_NODE
 import ch.dissem.apps.abit.util.Exports
-import ch.dissem.apps.abit.util.NetworkUtils
-import ch.dissem.apps.abit.util.Preferences
+import ch.dissem.apps.abit.util.network
+import ch.dissem.apps.abit.util.preferences
 import ch.dissem.bitmessage.entity.Plaintext
 import com.mikepenz.aboutlibraries.Libs
 import com.mikepenz.aboutlibraries.LibsBuilder
@@ -51,8 +51,7 @@ import java.util.*
 /**
  * @author Christian Basler
  */
-class SettingsFragment : PreferenceFragmentCompat(), SharedPreferences.OnSharedPreferenceChangeListener,
-    PreferenceFragmentCompat.OnPreferenceStartScreenCallback {
+class SettingsFragment : PreferenceFragmentCompat(), PreferenceFragmentCompat.OnPreferenceStartScreenCallback {
 
     override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
         setPreferencesFromResource(R.xml.preferences, rootKey)
@@ -103,7 +102,7 @@ class SettingsFragment : PreferenceFragmentCompat(), SharedPreferences.OnSharedP
             val bmc = Singleton.getBitmessageContext(ctx)
             bmc.internals.nodeRegistry.clear()
             bmc.cleanup()
-            Preferences.cleanupExportDirectory(ctx)
+            ctx.preferences.cleanupExportDirectory()
 
             uiThread {
                 Toast.makeText(
@@ -122,7 +121,7 @@ class SettingsFragment : PreferenceFragmentCompat(), SharedPreferences.OnSharedP
 
         indeterminateProgressDialog(R.string.export_data_summary, R.string.export_data).apply {
             doAsync {
-                val exportDirectory = Preferences.getExportDirectory(ctx)
+                val exportDirectory = ctx.preferences.exportDirectory
                 exportDirectory.mkdirs()
                 val file = Exports.exportData(exportDirectory, ctx)
                 val contentUri = getUriForFile(ctx, "ch.dissem.apps.abit.fileprovider", file)
@@ -161,7 +160,7 @@ class SettingsFragment : PreferenceFragmentCompat(), SharedPreferences.OnSharedP
     override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
         val ctx = context ?: throw IllegalStateException("No context available")
         when (requestCode) {
-            WRITE_EXPORT_REQUEST_CODE -> Preferences.cleanupExportDirectory(ctx)
+            WRITE_EXPORT_REQUEST_CODE -> ctx.preferences.cleanupExportDirectory()
             READ_IMPORT_REQUEST_CODE -> {
                 if (resultCode == Activity.RESULT_OK && data?.data != null) {
                     indeterminateProgressDialog(R.string.import_data_summary, R.string.import_data).apply {
@@ -187,24 +186,6 @@ class SettingsFragment : PreferenceFragmentCompat(), SharedPreferences.OnSharedP
         }
     }
 
-    override fun onSharedPreferenceChanged(sharedPreferences: SharedPreferences, key: String) {
-        when (key) {
-            PREFERENCE_SERVER_POW -> toggleSyncServerPOW(sharedPreferences)
-        }
-    }
-
-    private fun toggleSyncServerPOW(sharedPreferences: SharedPreferences) {
-        val node = sharedPreferences.getString(PREFERENCE_TRUSTED_NODE, null)
-        if (node != null) {
-            val ctx = context ?: throw IllegalStateException("No context available")
-            if (sharedPreferences.getBoolean(PREFERENCE_SERVER_POW, false)) {
-                SyncAdapter.startPowSync(ctx)
-            } else {
-                SyncAdapter.stopPowSync(ctx)
-            }
-        }
-    }
-
     private val connection = object : ServiceConnection {
         override fun onServiceConnected(name: ComponentName, service: IBinder) {
             if (service is BatchProcessorService.BatchBinder) {
@@ -250,11 +231,7 @@ class SettingsFragment : PreferenceFragmentCompat(), SharedPreferences.OnSharedP
 
     private fun connectivityChangeListener() =
         OnPreferenceChangeListener { _, _ ->
-            context?.let { ctx ->
-                if (Preferences.isFullNodeActive(ctx)) {
-                    NetworkUtils.scheduleNodeStart(ctx)
-                }
-            }
+            context?.network?.scheduleNodeStart()
             true
         }
 
diff --git a/app/src/main/java/ch/dissem/apps/abit/adapter/SwitchingProofOfWorkEngine.kt b/app/src/main/java/ch/dissem/apps/abit/adapter/SwitchingProofOfWorkEngine.kt
deleted file mode 100644
index 69df6ee..0000000
--- a/app/src/main/java/ch/dissem/apps/abit/adapter/SwitchingProofOfWorkEngine.kt
+++ /dev/null
@@ -1,48 +0,0 @@
-/*
- * Copyright 2016 Christian Basler
- *
- * 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 ch.dissem.apps.abit.adapter
-
-import android.content.Context
-import android.preference.PreferenceManager
-import ch.dissem.bitmessage.InternalContext
-import ch.dissem.bitmessage.ports.ProofOfWorkEngine
-
-/**
- * Switches between two [ProofOfWorkEngine]s depending on the configuration.
- *
- * @author Christian Basler
- */
-class SwitchingProofOfWorkEngine(
-        private val ctx: Context,
-        private val preference: String,
-        private val option: ProofOfWorkEngine,
-        private val fallback: ProofOfWorkEngine
-) : ProofOfWorkEngine, InternalContext.ContextHolder {
-
-    override fun calculateNonce(initialHash: ByteArray, target: ByteArray, callback: ProofOfWorkEngine.Callback) {
-        val preferences = PreferenceManager.getDefaultSharedPreferences(ctx)
-        if (preferences.getBoolean(preference, false)) {
-            option.calculateNonce(initialHash, target, callback)
-        } else {
-            fallback.calculateNonce(initialHash, target, callback)
-        }
-    }
-
-    override fun setContext(context: InternalContext) = listOf(option, fallback)
-            .filterIsInstance<InternalContext.ContextHolder>()
-            .forEach { it.setContext(context) }
-}
diff --git a/app/src/main/java/ch/dissem/apps/abit/dialog/FullNodeDialogActivity.kt b/app/src/main/java/ch/dissem/apps/abit/dialog/FullNodeDialogActivity.kt
index 985d6e4..9f86455 100644
--- a/app/src/main/java/ch/dissem/apps/abit/dialog/FullNodeDialogActivity.kt
+++ b/app/src/main/java/ch/dissem/apps/abit/dialog/FullNodeDialogActivity.kt
@@ -19,8 +19,8 @@ package ch.dissem.apps.abit.dialog
 import android.app.Activity
 import android.os.Bundle
 import ch.dissem.apps.abit.R
-import ch.dissem.apps.abit.util.NetworkUtils
-import ch.dissem.apps.abit.util.Preferences
+import ch.dissem.apps.abit.util.network
+import ch.dissem.apps.abit.util.preferences
 import kotlinx.android.synthetic.main.dialog_full_node.*
 
 /**
@@ -31,12 +31,12 @@ class FullNodeDialogActivity : Activity() {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.dialog_full_node)
         ok.setOnClickListener {
-            Preferences.setWifiOnly(this@FullNodeDialogActivity, false)
-            NetworkUtils.enableNode(applicationContext)
+            preferences.wifiOnly = false
+            network.enableNode()
             finish()
         }
         dismiss.setOnClickListener {
-            NetworkUtils.scheduleNodeStart(applicationContext)
+            network.scheduleNodeStart()
             finish()
         }
     }
diff --git a/app/src/main/java/ch/dissem/apps/abit/dialog/SelectEncodingDialogFragment.kt b/app/src/main/java/ch/dissem/apps/abit/dialog/SelectEncodingDialogFragment.kt
index 1f37e4f..9a7e1f0 100644
--- a/app/src/main/java/ch/dissem/apps/abit/dialog/SelectEncodingDialogFragment.kt
+++ b/app/src/main/java/ch/dissem/apps/abit/dialog/SelectEncodingDialogFragment.kt
@@ -49,7 +49,7 @@ class SelectEncodingDialogFragment : AppCompatDialogFragment() {
         when (encoding) {
             SIMPLE -> radioGroup.check(R.id.simple)
             EXTENDED -> radioGroup.check(R.id.extended)
-            else -> LOG.warn("Unexpected encoding: " + encoding)
+            else -> LOG.warn("Unexpected encoding: $encoding")
         }
         ok.setOnClickListener(View.OnClickListener {
             encoding = when (radioGroup.checkedRadioButtonId) {
diff --git a/app/src/main/java/ch/dissem/apps/abit/listener/MessageListener.kt b/app/src/main/java/ch/dissem/apps/abit/listener/MessageListener.kt
index a9405af..0ef4775 100644
--- a/app/src/main/java/ch/dissem/apps/abit/listener/MessageListener.kt
+++ b/app/src/main/java/ch/dissem/apps/abit/listener/MessageListener.kt
@@ -19,7 +19,7 @@ package ch.dissem.apps.abit.listener
 import android.content.Context
 import ch.dissem.apps.abit.MainActivity
 import ch.dissem.apps.abit.notification.NewMessageNotification
-import ch.dissem.apps.abit.util.Preferences
+import ch.dissem.apps.abit.util.preferences
 import ch.dissem.bitmessage.BitmessageContext
 import ch.dissem.bitmessage.entity.Plaintext
 import ch.dissem.bitmessage.ports.MessageRepository
@@ -50,7 +50,7 @@ class MessageListener(ctx: Context) : BitmessageContext.Listener.WithContext {
     private lateinit var conversationService: ConversationService
 
     init {
-        emulateConversations = Preferences.isEmulateConversations(ctx)
+        emulateConversations = ctx.preferences.emulateConversations
     }
 
     override fun receive(plaintext: Plaintext) {
@@ -81,7 +81,7 @@ class MessageListener(ctx: Context) : BitmessageContext.Listener.WithContext {
         }
     }
 
-    fun updateConversation(plaintext: Plaintext) {
+    private fun updateConversation(plaintext: Plaintext) {
         if (emulateConversations && plaintext.encoding != Plaintext.Encoding.EXTENDED) {
             conversationService.getSubject(listOf(plaintext))?.let { subject ->
                 plaintext.conversationId = UUID.nameUUIDFromBytes(subject.toByteArray())
diff --git a/app/src/main/java/ch/dissem/apps/abit/notification/NetworkNotification.kt b/app/src/main/java/ch/dissem/apps/abit/notification/NetworkNotification.kt
index abc024e..170e787 100644
--- a/app/src/main/java/ch/dissem/apps/abit/notification/NetworkNotification.kt
+++ b/app/src/main/java/ch/dissem/apps/abit/notification/NetworkNotification.kt
@@ -25,7 +25,7 @@ import android.support.v4.app.NotificationCompat
 import ch.dissem.apps.abit.MainActivity
 import ch.dissem.apps.abit.R
 import ch.dissem.apps.abit.service.BitmessageIntentService
-import ch.dissem.apps.abit.service.BitmessageService
+import ch.dissem.apps.abit.service.NodeStartupService
 import java.util.*
 import kotlin.concurrent.fixedRateTimer
 
@@ -51,9 +51,9 @@ class NetworkNotification(ctx: Context) : AbstractNotification(ctx) {
 
     @SuppressLint("StringFormatMatches")
     private fun update(): Boolean {
-        val running = BitmessageService.isRunning
+        val running = NodeStartupService.isRunning
         builder.setOngoing(running)
-        val connections = BitmessageService.status.getProperty("network", "connections")
+        val connections = NodeStartupService.status.getProperty("network", "connections")
         if (!running) {
             builder.setSmallIcon(R.drawable.ic_notification_full_node_disconnected)
             builder.setContentText(ctx.getString(R.string.connection_info_disconnected))
@@ -112,7 +112,6 @@ class NetworkNotification(ctx: Context) : AbstractNotification(ctx) {
         timer = fixedRateTimer(initialDelay = 10000, period = 10000) {
             if (!update()) {
                 cancel()
-                ctx.stopService(Intent(ctx, BitmessageService::class.java))
             }
             super@NetworkNotification.show()
         }
diff --git a/app/src/main/java/ch/dissem/apps/abit/pow/ServerPowEngine.kt b/app/src/main/java/ch/dissem/apps/abit/pow/ServerPowEngine.kt
deleted file mode 100644
index 39d8b1d..0000000
--- a/app/src/main/java/ch/dissem/apps/abit/pow/ServerPowEngine.kt
+++ /dev/null
@@ -1,83 +0,0 @@
-/*
- * Copyright 2016 Christian Basler
- *
- * 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 ch.dissem.apps.abit.pow
-
-import android.content.Context
-import ch.dissem.apps.abit.service.Singleton
-import ch.dissem.apps.abit.synchronization.SyncAdapter
-import ch.dissem.apps.abit.util.Preferences
-import ch.dissem.bitmessage.InternalContext
-import ch.dissem.bitmessage.extensions.CryptoCustomMessage
-import ch.dissem.bitmessage.extensions.pow.ProofOfWorkRequest
-import ch.dissem.bitmessage.extensions.pow.ProofOfWorkRequest.Request.CALCULATE
-import ch.dissem.bitmessage.ports.ProofOfWorkEngine
-import ch.dissem.bitmessage.utils.Singleton.cryptography
-import org.slf4j.LoggerFactory
-import java.util.concurrent.ExecutorService
-import java.util.concurrent.Executors
-
-/**
- * @author Christian Basler
- */
-class ServerPowEngine(private val ctx: Context) : ProofOfWorkEngine, InternalContext.ContextHolder {
-    private lateinit var context: InternalContext
-
-    private val pool: ExecutorService
-
-    init {
-        pool = Executors.newCachedThreadPool { r ->
-            val thread = Executors.defaultThreadFactory().newThread(r)
-            thread.priority = Thread.MIN_PRIORITY
-            thread
-        }
-    }
-
-    override fun calculateNonce(initialHash: ByteArray, target: ByteArray, callback: ProofOfWorkEngine.Callback) =
-        pool.execute {
-            val identity = Singleton.getIdentity(ctx) ?: throw RuntimeException("No Identity for calculating POW")
-
-            val request = ProofOfWorkRequest(identity, initialHash,
-                    CALCULATE, target)
-            SyncAdapter.startPowSync(ctx)
-            try {
-                val cryptoMsg = CryptoCustomMessage(request)
-                cryptoMsg.signAndEncrypt(
-                        identity,
-                        cryptography().createPublicKey(identity.publicDecryptionKey)
-                )
-                val node = Preferences.getTrustedNode(ctx)
-                if (node == null) {
-                    LOG.error("trusted node is not defined")
-                } else {
-                    context.networkHandler.send(
-                            node,
-                            Preferences.getTrustedNodePort(ctx),
-                            cryptoMsg)
-                }
-            } catch (e: Exception) {
-                LOG.error(e.message, e)
-            }
-        }
-
-    override fun setContext(context: InternalContext) {
-        this.context = context
-    }
-
-    companion object {
-        private val LOG = LoggerFactory.getLogger(ServerPowEngine::class.java)
-    }
-}
diff --git a/app/src/main/java/ch/dissem/apps/abit/service/BitmessageIntentService.kt b/app/src/main/java/ch/dissem/apps/abit/service/BitmessageIntentService.kt
index 7156ce9..46fcc94 100644
--- a/app/src/main/java/ch/dissem/apps/abit/service/BitmessageIntentService.kt
+++ b/app/src/main/java/ch/dissem/apps/abit/service/BitmessageIntentService.kt
@@ -18,7 +18,7 @@ package ch.dissem.apps.abit.service
 
 import android.app.IntentService
 import android.content.Intent
-import ch.dissem.apps.abit.util.NetworkUtils
+import ch.dissem.apps.abit.util.network
 import ch.dissem.bitmessage.BitmessageContext
 import ch.dissem.bitmessage.entity.Plaintext
 
@@ -44,10 +44,10 @@ class BitmessageIntentService : IntentService("BitmessageIntentService") {
                 Singleton.getMessageListener(this).resetNotification()
             }
             if (it.hasExtra(EXTRA_STARTUP_NODE)) {
-                NetworkUtils.enableNode(this)
+                network.enableNode()
             }
             if (it.hasExtra(EXTRA_SHUTDOWN_NODE)) {
-                NetworkUtils.disableNode(this)
+                network.disableNode()
             }
         }
     }
diff --git a/app/src/main/java/ch/dissem/apps/abit/service/BitmessageService.kt b/app/src/main/java/ch/dissem/apps/abit/service/BitmessageService.kt
deleted file mode 100644
index d22b6fa..0000000
--- a/app/src/main/java/ch/dissem/apps/abit/service/BitmessageService.kt
+++ /dev/null
@@ -1,113 +0,0 @@
-/*
- * Copyright 2016 Christian Basler
- *
- * 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 ch.dissem.apps.abit.service
-
-import android.app.Service
-import android.content.BroadcastReceiver
-import android.content.Context
-import android.content.Intent
-import android.content.IntentFilter
-import android.net.ConnectivityManager
-import android.os.Handler
-import ch.dissem.apps.abit.notification.NetworkNotification
-import ch.dissem.apps.abit.notification.NetworkNotification.Companion.NETWORK_NOTIFICATION_ID
-import ch.dissem.apps.abit.util.Preferences
-import ch.dissem.bitmessage.BitmessageContext
-import ch.dissem.bitmessage.utils.Property
-import org.jetbrains.anko.doAsync
-
-/**
- * Define a Service that returns an IBinder for the
- * sync adapter class, allowing the sync adapter framework to call
- * onPerformSync().
- */
-class BitmessageService : Service() {
-
-    private val bmc: BitmessageContext by lazy { Singleton.getBitmessageContext(this) }
-    private lateinit var notification: NetworkNotification
-
-    private val connectivityReceiver: BroadcastReceiver = object : BroadcastReceiver() {
-        override fun onReceive(context: Context, intent: Intent?) {
-            if (bmc.isRunning() && !Preferences.isConnectionAllowed(this@BitmessageService)) {
-                bmc.shutdown()
-            }
-        }
-    }
-
-    private val cleanupHandler = Handler()
-    private val cleanupTask: Runnable = object : Runnable {
-        override fun run() {
-            bmc.cleanup()
-            if (isRunning) {
-                cleanupHandler.postDelayed(this, 24 * 60 * 60 * 1000L) // once a day
-            }
-        }
-    }
-
-    override fun onCreate() {
-        registerReceiver(
-            connectivityReceiver,
-            IntentFilter().apply {
-                addAction(ConnectivityManager.CONNECTIVITY_ACTION)
-                addAction(Intent.ACTION_BATTERY_CHANGED)
-            }
-        )
-        notification = NetworkNotification(this)
-        running = false
-    }
-
-    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
-        if (!isRunning) {
-            running = true
-            notification.connecting()
-            startForeground(NETWORK_NOTIFICATION_ID, notification.notification)
-            if (!bmc.isRunning()) {
-                bmc.startup()
-            }
-            notification.show()
-            cleanupHandler.postDelayed(cleanupTask, 24 * 60 * 60 * 1000L)
-        }
-        return Service.START_STICKY
-    }
-
-    override fun onDestroy() {
-        if (bmc.isRunning()) {
-            bmc.shutdown()
-        }
-        running = false
-        notification.showShutdown()
-        cleanupHandler.removeCallbacks(cleanupTask)
-        doAsync {
-            bmc.cleanup()
-        }
-        unregisterReceiver(connectivityReceiver)
-        stopSelf()
-    }
-
-    override fun onBind(intent: Intent) = null
-
-    companion object {
-        @Volatile
-        private var running = false
-
-        val isRunning: Boolean
-            get() = running && Singleton.bitmessageContext?.isRunning() == true
-
-        val status: Property
-            get() = Singleton.bitmessageContext?.status() ?: Property("bitmessage context")
-    }
-}
diff --git a/app/src/main/java/ch/dissem/apps/abit/service/CleanupService.kt b/app/src/main/java/ch/dissem/apps/abit/service/CleanupService.kt
new file mode 100644
index 0000000..bd2a869
--- /dev/null
+++ b/app/src/main/java/ch/dissem/apps/abit/service/CleanupService.kt
@@ -0,0 +1,18 @@
+package ch.dissem.apps.abit.service
+
+import android.app.job.JobParameters
+import android.app.job.JobService
+import org.jetbrains.anko.doAsync
+
+class CleanupService : JobService() {
+
+    override fun onStartJob(params: JobParameters?): Boolean {
+        doAsync {
+            Singleton.getBitmessageContext(this@CleanupService).cleanup()
+            jobFinished(params, false)
+        }
+        return true
+    }
+
+    override fun onStopJob(params: JobParameters?) = false
+}
diff --git a/app/src/main/java/ch/dissem/apps/abit/service/NodeStartupService.kt b/app/src/main/java/ch/dissem/apps/abit/service/NodeStartupService.kt
new file mode 100644
index 0000000..9a2b8e2
--- /dev/null
+++ b/app/src/main/java/ch/dissem/apps/abit/service/NodeStartupService.kt
@@ -0,0 +1,93 @@
+package ch.dissem.apps.abit.service
+
+import android.app.job.JobParameters
+import android.app.job.JobService
+import android.content.BroadcastReceiver
+import android.content.Context
+import android.content.Intent
+import android.content.IntentFilter
+import android.net.ConnectivityManager
+import ch.dissem.apps.abit.notification.NetworkNotification
+import ch.dissem.apps.abit.util.network
+import ch.dissem.apps.abit.util.preferences
+import ch.dissem.bitmessage.BitmessageContext
+import ch.dissem.bitmessage.utils.Property
+import org.jetbrains.anko.doAsync
+
+/**
+ * Starts the full node if
+ * * it is active
+ * * it is not already running
+ *
+ * And stops it when the preconditions for the job (unmetered network) aren't met anymore.
+ */
+class NodeStartupService : JobService() {
+    private val bmc: BitmessageContext by lazy { Singleton.getBitmessageContext(this) }
+
+    private lateinit var notification: NetworkNotification
+
+    private val connectivityReceiver: BroadcastReceiver = object : BroadcastReceiver() {
+        override fun onReceive(context: Context, intent: Intent?) {
+            if (bmc.isRunning() && !preferences.connectionAllowed) {
+                bmc.shutdown()
+            }
+        }
+    }
+
+    override fun onStartJob(params: JobParameters?): Boolean {
+        if (preferences.online) {
+            registerReceiver(
+                connectivityReceiver,
+                IntentFilter().apply {
+                    addAction(ConnectivityManager.CONNECTIVITY_ACTION)
+                    addAction(Intent.ACTION_BATTERY_CHANGED)
+                }
+            )
+            notification = NetworkNotification(this)
+            NodeStartupService.running = false
+
+            if (!isRunning) {
+                running = true
+                notification.connecting()
+                if (!bmc.isRunning()) {
+                    bmc.startup()
+                }
+                notification.show()
+            }
+        }
+        return true
+    }
+
+    override fun onDestroy() {
+        if (bmc.isRunning()) {
+            bmc.shutdown()
+        }
+        running = false
+        notification.showShutdown()
+        doAsync {
+            bmc.cleanup()
+        }
+        unregisterReceiver(connectivityReceiver)
+        stopSelf()
+    }
+
+    /**
+     * Don't actually stop the service, otherwise it will be stopped after 1 or 10 minutes
+     * depending on Android version.
+     */
+    override fun onStopJob(params: JobParameters?): Boolean {
+        network.scheduleNodeStart()
+        return false
+    }
+
+    companion object {
+        @Volatile
+        private var running = false
+
+        val isRunning: Boolean
+            get() = running && Singleton.bitmessageContext?.isRunning() == true
+
+        val status: Property
+            get() = Singleton.bitmessageContext?.status() ?: Property("bitmessage context")
+    }
+}
diff --git a/app/src/main/java/ch/dissem/apps/abit/service/Singleton.kt b/app/src/main/java/ch/dissem/apps/abit/service/Singleton.kt
index a207edd..705964c 100644
--- a/app/src/main/java/ch/dissem/apps/abit/service/Singleton.kt
+++ b/app/src/main/java/ch/dissem/apps/abit/service/Singleton.kt
@@ -21,11 +21,8 @@ import android.widget.Toast
 import ch.dissem.apps.abit.MainActivity
 import ch.dissem.apps.abit.R
 import ch.dissem.apps.abit.adapter.SwipeableMessageAdapter
-import ch.dissem.apps.abit.adapter.SwitchingProofOfWorkEngine
 import ch.dissem.apps.abit.listener.MessageListener
-import ch.dissem.apps.abit.pow.ServerPowEngine
 import ch.dissem.apps.abit.repository.*
-import ch.dissem.apps.abit.util.Constants
 import ch.dissem.apps.abit.util.Observable
 import ch.dissem.bitmessage.BitmessageContext
 import ch.dissem.bitmessage.cryptography.sc.SpongyCryptography
@@ -107,11 +104,7 @@ object Singleton {
                 TTL.pubkey = 2 * DAY
                 val ctx = context.applicationContext
                 val sqlHelper = SqlHelper(ctx)
-                proofOfWorkEngine = SwitchingProofOfWorkEngine(
-                    ctx, Constants.PREFERENCE_SERVER_POW,
-                    ServerPowEngine(ctx),
-                    ServicePowEngine(ctx)
-                )
+                proofOfWorkEngine = ServicePowEngine(ctx)
                 cryptography = SpongyCryptography()
                 nodeRegistry = AndroidNodeRegistry(sqlHelper)
                 inventory = AndroidInventory(sqlHelper)
@@ -138,8 +131,6 @@ object Singleton {
 
     fun getAddressRepository(ctx: Context) = getBitmessageContext(ctx).addresses as AndroidAddressRepository
 
-    fun getProofOfWorkRepository(ctx: Context) = powRepo ?: getBitmessageContext(ctx).internals.proofOfWorkRepository
-
     fun getIdentity(ctx: Context): BitmessageAddress? =
         init<BitmessageAddress?>(ctx, { identity }, { identity = it }) { bmc ->
             val identities = bmc.addresses.getIdentities()
diff --git a/app/src/main/java/ch/dissem/apps/abit/service/StartServiceReceiver.kt b/app/src/main/java/ch/dissem/apps/abit/service/StartServiceReceiver.kt
index 4601592..f5451ef 100644
--- a/app/src/main/java/ch/dissem/apps/abit/service/StartServiceReceiver.kt
+++ b/app/src/main/java/ch/dissem/apps/abit/service/StartServiceReceiver.kt
@@ -3,18 +3,17 @@ package ch.dissem.apps.abit.service
 import android.content.BroadcastReceiver
 import android.content.Context
 import android.content.Intent
-import ch.dissem.apps.abit.util.NetworkUtils
-import ch.dissem.apps.abit.util.Preferences
+import android.content.Intent.ACTION_BOOT_COMPLETED
+import ch.dissem.apps.abit.util.network
+import ch.dissem.apps.abit.util.preferences
 
 /**
  * Starts the Bitmessage "full node" service if conditions allow it
  */
 class StartServiceReceiver : BroadcastReceiver() {
     override fun onReceive(context: Context, intent: Intent?) {
-        if (intent?.action == "android.intent.action.BOOT_COMPLETED") {
-            if (Preferences.isFullNodeActive(context)) {
-                NetworkUtils.enableNode(context, false)
-            }
+        if (intent?.action == ACTION_BOOT_COMPLETED && context.preferences.online) {
+            context.network.enableNode(false)
         }
     }
 }
diff --git a/app/src/main/java/ch/dissem/apps/abit/service/StartupNodeOnWifiService.kt b/app/src/main/java/ch/dissem/apps/abit/service/StartupNodeOnWifiService.kt
deleted file mode 100644
index 81f23f4..0000000
--- a/app/src/main/java/ch/dissem/apps/abit/service/StartupNodeOnWifiService.kt
+++ /dev/null
@@ -1,33 +0,0 @@
-package ch.dissem.apps.abit.service
-
-import android.app.job.JobParameters
-import android.app.job.JobService
-import android.os.Build
-import android.support.annotation.RequiresApi
-import ch.dissem.apps.abit.util.NetworkUtils
-import ch.dissem.apps.abit.util.Preferences
-
-/**
- * Starts the full node if
- * * it is active
- * * it is not already running
- *
- * And stops it when the preconditions for the job (unmetered network) aren't met anymore.
- */
-class StartupNodeOnWifiService : JobService() {
-
-    override fun onStartJob(params: JobParameters?): Boolean {
-        val bmc = Singleton.getBitmessageContext(this)
-        if (Preferences.isFullNodeActive(this) && !bmc.isRunning()) {
-            NetworkUtils.doStartBitmessageService(applicationContext)
-        }
-        return true
-    }
-
-    /**
-     * Don't actually stop the service, otherwise it will be stopped after 1 or 10 minutes
-     * depending on Android version.
-     */
-    override fun onStopJob(params: JobParameters?) = Preferences.isFullNodeActive(this)
-
-}
diff --git a/app/src/main/java/ch/dissem/apps/abit/synchronization/Authenticator.kt b/app/src/main/java/ch/dissem/apps/abit/synchronization/Authenticator.kt
deleted file mode 100644
index b821456..0000000
--- a/app/src/main/java/ch/dissem/apps/abit/synchronization/Authenticator.kt
+++ /dev/null
@@ -1,62 +0,0 @@
-/*
- * Copyright 2016 Christian Basler
- *
- * 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 ch.dissem.apps.abit.synchronization
-
-import android.accounts.AbstractAccountAuthenticator
-import android.accounts.Account
-import android.accounts.AccountAuthenticatorResponse
-import android.accounts.NetworkErrorException
-import android.content.Context
-import android.os.Bundle
-
-/**
- * Implement AbstractAccountAuthenticator and stub out all
- * of its methods
- */
-class Authenticator(context: Context) : AbstractAccountAuthenticator(context) {
-
-    override fun editProperties(r: AccountAuthenticatorResponse, s: String) =
-            throw UnsupportedOperationException("Editing properties is not supported")
-
-    // Don't add additional accounts
-    @Throws(NetworkErrorException::class)
-    override fun addAccount(r: AccountAuthenticatorResponse, s: String, s2: String, strings: Array<String>, bundle: Bundle) = null
-
-    // Ignore attempts to confirm credentials
-    @Throws(NetworkErrorException::class)
-    override fun confirmCredentials(r: AccountAuthenticatorResponse, account: Account, bundle: Bundle) = null
-
-    @Throws(NetworkErrorException::class)
-    override fun getAuthToken(r: AccountAuthenticatorResponse, account: Account, s: String, bundle: Bundle) =
-            throw UnsupportedOperationException("Getting an authentication token is not supported")
-
-    override fun getAuthTokenLabel(s: String) =
-            throw UnsupportedOperationException("Getting a label for the auth token is not supported")
-
-    @Throws(NetworkErrorException::class)
-    override fun updateCredentials(r: AccountAuthenticatorResponse, account: Account, s: String, bundle: Bundle) =
-            throw UnsupportedOperationException("Updating user credentials is not supported")
-
-    @Throws(NetworkErrorException::class)
-    override fun hasFeatures(r: AccountAuthenticatorResponse, account: Account, strings: Array<String>) =
-            throw UnsupportedOperationException("Checking features for the account is not supported")
-
-    companion object {
-        val ACCOUNT_SYNC = Account("Bitmessage", "ch.dissem.bitmessage")
-        val ACCOUNT_POW = Account("Proof of Work ", "ch.dissem.bitmessage")
-    }
-}
diff --git a/app/src/main/java/ch/dissem/apps/abit/synchronization/AuthenticatorService.kt b/app/src/main/java/ch/dissem/apps/abit/synchronization/AuthenticatorService.kt
deleted file mode 100644
index 345da0c..0000000
--- a/app/src/main/java/ch/dissem/apps/abit/synchronization/AuthenticatorService.kt
+++ /dev/null
@@ -1,42 +0,0 @@
-/*
- * Copyright 2016 Christian Basler
- *
- * 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 ch.dissem.apps.abit.synchronization
-
-import android.app.Service
-import android.content.Intent
-
-/**
- * A bound Service that instantiates the authenticator
- * when started.
- */
-class AuthenticatorService : Service() {
-    /**
-     * Instance field that stores the authenticator object
-     */
-    private var authenticator: Authenticator? = null
-
-    override fun onCreate() {
-        // Create a new authenticator object
-        authenticator = Authenticator(this)
-    }
-
-    /*
-     * When the system binds to this Service to make the RPC call
-     * return the authenticator's IBinder.
-     */
-    override fun onBind(intent: Intent) = authenticator?.iBinder
-}
diff --git a/app/src/main/java/ch/dissem/apps/abit/synchronization/StubProvider.kt b/app/src/main/java/ch/dissem/apps/abit/synchronization/StubProvider.kt
deleted file mode 100644
index d456928..0000000
--- a/app/src/main/java/ch/dissem/apps/abit/synchronization/StubProvider.kt
+++ /dev/null
@@ -1,72 +0,0 @@
-/*
- * Copyright 2016 Christian Basler
- *
- * 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 ch.dissem.apps.abit.synchronization
-
-import android.content.ContentProvider
-import android.content.ContentValues
-import android.net.Uri
-
-/*
- * Define an implementation of ContentProvider that stubs out
- * all methods
- */
-class StubProvider : ContentProvider() {
-
-    /**
-     * Always return true, indicating that the
-     * provider loaded correctly.
-     */
-    override fun onCreate() = true
-
-    /**
-     * Return no type for MIME type
-     */
-    override fun getType(uri: Uri) = null
-
-    /**
-     * query() always returns no results
-     */
-    override fun query(
-        uri: Uri,
-        projection: Array<String>?,
-        selection: String?,
-        selectionArgs: Array<String>?,
-        sortOrder: String?) = null
-
-    /**
-     * insert() always returns null (no URI)
-     */
-    override fun insert(uri: Uri, values: ContentValues?) = null
-
-    /**
-     * delete() always returns "no rows affected" (0)
-     */
-    override fun delete(uri: Uri, selection: String?, selectionArgs: Array<String>?) = 0
-
-    /**
-     * update() always returns "no rows affected" (0)
-     */
-    override fun update(
-        uri: Uri,
-        values: ContentValues?,
-        selection: String?,
-        selectionArgs: Array<String>?) = 0
-
-    companion object {
-        const val AUTHORITY = "ch.dissem.apps.abit.provider"
-    }
-}
diff --git a/app/src/main/java/ch/dissem/apps/abit/synchronization/SyncAdapter.kt b/app/src/main/java/ch/dissem/apps/abit/synchronization/SyncAdapter.kt
deleted file mode 100644
index 8dc6d22..0000000
--- a/app/src/main/java/ch/dissem/apps/abit/synchronization/SyncAdapter.kt
+++ /dev/null
@@ -1,188 +0,0 @@
-/*
- * Copyright 2016 Christian Basler
- *
- * 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 ch.dissem.apps.abit.synchronization
-
-import android.accounts.Account
-import android.accounts.AccountManager
-import android.content.*
-import android.os.Bundle
-import ch.dissem.apps.abit.service.Singleton
-import ch.dissem.apps.abit.synchronization.Authenticator.Companion.ACCOUNT_POW
-import ch.dissem.apps.abit.synchronization.Authenticator.Companion.ACCOUNT_SYNC
-import ch.dissem.apps.abit.synchronization.StubProvider.Companion.AUTHORITY
-import ch.dissem.apps.abit.util.NetworkUtils
-import ch.dissem.apps.abit.util.Preferences
-import ch.dissem.bitmessage.exception.DecryptionFailedException
-import ch.dissem.bitmessage.extensions.CryptoCustomMessage
-import ch.dissem.bitmessage.extensions.pow.ProofOfWorkRequest
-import ch.dissem.bitmessage.extensions.pow.ProofOfWorkRequest.Request.CALCULATE
-import ch.dissem.bitmessage.extensions.pow.ProofOfWorkRequest.Request.COMPLETE
-import ch.dissem.bitmessage.utils.Singleton.cryptography
-import org.slf4j.LoggerFactory
-import java.io.IOException
-
-/**
- * Sync Adapter to synchronize with the Bitmessage network - fetches
- * new objects and then disconnects.
- */
-class SyncAdapter(context: Context, autoInitialize: Boolean) : AbstractThreadedSyncAdapter(context, autoInitialize) {
-
-    private val bmc = Singleton.getBitmessageContext(context)
-
-    override fun onPerformSync(
-        account: Account,
-        extras: Bundle,
-        authority: String,
-        provider: ContentProviderClient,
-        syncResult: SyncResult
-    ) {
-        try {
-            if (account == ACCOUNT_SYNC) {
-                if (Preferences.isConnectionAllowed(context)) {
-                    syncData()
-                }
-            } else if (account == ACCOUNT_POW) {
-                syncPOW()
-            } else {
-                syncResult.stats.numAuthExceptions++
-            }
-        } catch (e: IOException) {
-            syncResult.stats.numIoExceptions++
-        } catch (e: DecryptionFailedException) {
-            syncResult.stats.numAuthExceptions++
-        }
-
-    }
-
-    private fun syncData() {
-        // If the Bitmessage context acts as a full node, synchronization isn't necessary
-        if (bmc.isRunning()) {
-            LOG.info("Synchronization skipped, Abit is acting as a full node")
-            return
-        }
-        val trustedNode = Preferences.getTrustedNode(context)
-        if (trustedNode == null) {
-            // As Abit tends to get killed by the system, let's leverage the sync mechanism to start it again:
-            NetworkUtils.scheduleNodeStart(context)
-            return
-        }
-        LOG.info("Synchronization started")
-        bmc.synchronize(
-            trustedNode,
-            Preferences.getTrustedNodePort(context),
-            Preferences.getTimeoutInSeconds(context),
-            true
-        )
-        LOG.info("Synchronization finished")
-    }
-
-    private fun syncPOW() {
-        val identity = Singleton.getIdentity(context)
-        if (identity == null) {
-            LOG.info("No identity available - skipping POW synchronization")
-            return
-        }
-        val trustedNode = Preferences.getTrustedNode(context)
-        if (trustedNode == null) {
-            LOG.info("Trusted node not available, disabling POW synchronization")
-            stopPowSync(context)
-            return
-        }
-        // If the Bitmessage context acts as a full node, synchronization isn't necessary
-        LOG.info("Looking for completed POW")
-
-        val privateKey =
-            identity.privateKey?.privateEncryptionKey ?: throw IllegalStateException("Identity without private key")
-        val signingKey = cryptography().createPublicKey(identity.publicDecryptionKey)
-        val reader = ProofOfWorkRequest.Reader(identity)
-        val powRepo = Singleton.getProofOfWorkRepository(context)
-        val items = powRepo.getItems()
-        for (initialHash in items) {
-            val (objectMessage, nonceTrialsPerByte, extraBytes) = powRepo.getItem(initialHash)
-            val target = cryptography().getProofOfWorkTarget(objectMessage, nonceTrialsPerByte, extraBytes)
-            val cryptoMsg = CryptoCustomMessage(
-                ProofOfWorkRequest(identity, initialHash, CALCULATE, target)
-            )
-            cryptoMsg.signAndEncrypt(identity, signingKey)
-            val response = bmc.send(
-                trustedNode,
-                Preferences.getTrustedNodePort(context),
-                cryptoMsg
-            )
-            if (response.isError) {
-                LOG.error("Server responded with error: ${String(response.getData())}")
-            } else {
-                val (_, _, request, data) = CryptoCustomMessage.read(response, reader).decrypt(privateKey)
-                if (request == COMPLETE) {
-                    bmc.internals.proofOfWorkService.onNonceCalculated(initialHash, data)
-                }
-            }
-        }
-        if (items.isEmpty()) {
-            stopPowSync(context)
-        }
-        LOG.info("Synchronization finished")
-    }
-
-    companion object {
-        private val LOG = LoggerFactory.getLogger(SyncAdapter::class.java)
-
-        private const val SYNC_FREQUENCY = 15 * 60L // seconds
-
-        fun startSync(ctx: Context) {
-            // Create account, if it's missing. (Either first run, or user has deleted account.)
-            val account = addAccount(ctx, ACCOUNT_SYNC)
-
-            // Recommend a schedule for automatic synchronization. The system may modify this based
-            // on other scheduled syncs and network utilization.
-            ContentResolver.addPeriodicSync(account, AUTHORITY, Bundle(), SYNC_FREQUENCY)
-        }
-
-        fun stopSync(ctx: Context) {
-            // Create account, if it's missing. (Either first run, or user has deleted account.)
-            val account = addAccount(ctx, ACCOUNT_SYNC)
-
-            ContentResolver.removePeriodicSync(account, AUTHORITY, Bundle())
-        }
-
-        fun startPowSync(ctx: Context) {
-            // Create account, if it's missing. (Either first run, or user has deleted account.)
-            val account = addAccount(ctx, ACCOUNT_POW)
-
-            // Recommend a schedule for automatic synchronization. The system may modify this based
-            // on other scheduled syncs and network utilization.
-            ContentResolver.addPeriodicSync(account, AUTHORITY, Bundle(), SYNC_FREQUENCY)
-        }
-
-        fun stopPowSync(ctx: Context) {
-            // Create account, if it's missing. (Either first run, or user has deleted account.)
-            val account = addAccount(ctx, ACCOUNT_POW)
-
-            ContentResolver.removePeriodicSync(account, AUTHORITY, Bundle())
-        }
-
-        private fun addAccount(ctx: Context, account: Account): Account {
-            if (AccountManager.get(ctx).addAccountExplicitly(account, null, null)) {
-                // Inform the system that this account supports sync
-                ContentResolver.setIsSyncable(account, AUTHORITY, 1)
-                // Inform the system that this account is eligible for auto sync when the network is up
-                ContentResolver.setSyncAutomatically(account, AUTHORITY, true)
-            }
-            return account
-        }
-    }
-}
diff --git a/app/src/main/java/ch/dissem/apps/abit/synchronization/SyncService.kt b/app/src/main/java/ch/dissem/apps/abit/synchronization/SyncService.kt
deleted file mode 100644
index a1b581e..0000000
--- a/app/src/main/java/ch/dissem/apps/abit/synchronization/SyncService.kt
+++ /dev/null
@@ -1,50 +0,0 @@
-/*
- * Copyright 2016 Christian Basler
- *
- * 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 ch.dissem.apps.abit.synchronization
-
-import android.app.Service
-import android.content.Intent
-
-/**
- * Define a Service that returns an IBinder for the
- * sync adapter class, allowing the sync adapter framework to call
- * onPerformSync().
- */
-class SyncService : Service() {
-
-    /**
-     * Instantiate the sync adapter object.
-     */
-    override fun onCreate() = synchronized(syncAdapterLock) {
-        if (syncAdapter == null) {
-            syncAdapter = SyncAdapter(this, true)
-        }
-    }
-
-    /**
-     * Return an object that allows the system to invoke
-     * the sync adapter.
-     */
-    override fun onBind(intent: Intent) = syncAdapter?.syncAdapterBinder
-
-    companion object {
-        // Storage for an instance of the sync adapter
-        private var syncAdapter: SyncAdapter? = null
-        // Object to use as a thread-safe lock
-        private val syncAdapterLock = Any()
-    }
-}
diff --git a/app/src/main/java/ch/dissem/apps/abit/util/Constants.kt b/app/src/main/java/ch/dissem/apps/abit/util/Constants.kt
index 5fd22a9..7523420 100644
--- a/app/src/main/java/ch/dissem/apps/abit/util/Constants.kt
+++ b/app/src/main/java/ch/dissem/apps/abit/util/Constants.kt
@@ -22,13 +22,10 @@ import java.util.regex.Pattern
  * @author Christian Basler
  */
 object Constants {
+    const val PREFERENCE_ONLINE = "online"
     const val PREFERENCE_WIFI_ONLY = "wifi_only"
     const val PREFERENCE_REQUIRE_CHARGING = "require_charging"
     const val PREFERENCE_EMULATE_CONVERSATIONS = "emulate_conversations"
-    const val PREFERENCE_TRUSTED_NODE = "trusted_node"
-    const val PREFERENCE_SYNC_TIMEOUT = "sync_timeout"
-    const val PREFERENCE_SERVER_POW = "server_pow"
-    const val PREFERENCE_FULL_NODE = "full_node"
     const val PREFERENCE_REQUEST_ACK = "request_acknowledgments"
     const val PREFERENCE_POW_AVERAGE = "average_pow_time_ms"
     const val PREFERENCE_POW_COUNT = "pow_count"
diff --git a/app/src/main/java/ch/dissem/apps/abit/util/NetworkUtils.kt b/app/src/main/java/ch/dissem/apps/abit/util/NetworkUtils.kt
index 8a089fb..3ee1836 100644
--- a/app/src/main/java/ch/dissem/apps/abit/util/NetworkUtils.kt
+++ b/app/src/main/java/ch/dissem/apps/abit/util/NetworkUtils.kt
@@ -6,20 +6,21 @@ import android.app.job.JobScheduler
 import android.content.ComponentName
 import android.content.Context
 import android.content.Intent
-import android.support.v4.content.ContextCompat
+import android.os.Build
 import ch.dissem.apps.abit.dialog.FullNodeDialogActivity
-import ch.dissem.apps.abit.service.BitmessageService
-import ch.dissem.apps.abit.service.StartupNodeOnWifiService
+import ch.dissem.apps.abit.service.CleanupService
+import ch.dissem.apps.abit.service.NodeStartupService
+import java.lang.ref.WeakReference
+import java.util.concurrent.TimeUnit
 
+val Context.network get() = NetworkUtils.getInstance(this)
 
-object NetworkUtils {
+class NetworkUtils internal constructor(private val ctx: Context) {
 
-    fun enableNode(ctx: Context, ask: Boolean = true) {
-        Preferences.setFullNodeActive(ctx, true)
+    private val jobScheduler by lazy { ctx.getSystemService(Context.JOB_SCHEDULER_SERVICE) as JobScheduler }
 
-        if (Preferences.isConnectionAllowed(ctx) || !ask) {
-            scheduleNodeStart(ctx)
-        } else {
+    fun enableNode(ask: Boolean = true) {
+        if (ask && !ctx.preferences.connectionAllowed) {
             // Ask for connection
             val dialogIntent = Intent(ctx, FullNodeDialogActivity::class.java)
             if (ctx !is Activity) {
@@ -27,30 +28,50 @@ object NetworkUtils {
                 ctx.sendBroadcast(Intent(Intent.ACTION_CLOSE_SYSTEM_DIALOGS))
             }
             ctx.startActivity(dialogIntent)
+        } else {
+            scheduleNodeStart()
         }
     }
 
-    fun doStartBitmessageService(ctx: Context) {
-        ContextCompat.startForegroundService(ctx, Intent(ctx, BitmessageService::class.java))
+    fun disableNode() {
+        jobScheduler.cancelAll()
     }
 
-    fun disableNode(ctx: Context) {
-        Preferences.setFullNodeActive(ctx, false)
-        ctx.stopService(Intent(ctx, BitmessageService::class.java))
-    }
+    fun scheduleNodeStart() {
+        JobInfo.Builder(0, ComponentName(ctx, NodeStartupService::class.java)).let { builder ->
+            when {
+                ctx.preferences.wifiOnly ->
+                    builder.setRequiredNetworkType(JobInfo.NETWORK_TYPE_UNMETERED)
+                Build.VERSION.SDK_INT >= Build.VERSION_CODES.N ->
+                    builder.setRequiredNetworkType(JobInfo.NETWORK_TYPE_NOT_ROAMING)
+                else ->
+                    builder.setRequiredNetworkType(JobInfo.NETWORK_TYPE_ANY)
+            }
+            builder.setRequiresCharging(ctx.preferences.requireCharging)
+            builder.setPersisted(true)
 
-    fun scheduleNodeStart(ctx: Context) {
-        val jobScheduler = ctx.getSystemService(Context.JOB_SCHEDULER_SERVICE) as JobScheduler
-        val serviceComponent = ComponentName(ctx, StartupNodeOnWifiService::class.java)
-        val builder = JobInfo.Builder(0, serviceComponent)
-        if (Preferences.isWifiOnly(ctx)) {
-            builder.setRequiredNetworkType(JobInfo.NETWORK_TYPE_UNMETERED)
+            jobScheduler.schedule(builder.build())
         }
-        if (Preferences.requireCharging(ctx)) {
+
+        JobInfo.Builder(1, ComponentName(ctx, CleanupService::class.java)).let { builder ->
+            builder.setPeriodic(TimeUnit.DAYS.toMillis(1))
+            builder.setRequiresDeviceIdle(true)
             builder.setRequiresCharging(true)
+
+            jobScheduler.schedule(builder.build())
+        }
+    }
+
+    companion object {
+        private var instance: WeakReference<NetworkUtils>? = null
+
+        internal fun getInstance(ctx: Context): NetworkUtils {
+            var networkUtils = instance?.get()
+            if (networkUtils == null) {
+                networkUtils = NetworkUtils(ctx.applicationContext)
+                instance = WeakReference(networkUtils)
+            }
+            return networkUtils
         }
-        builder.setBackoffCriteria(0L, JobInfo.BACKOFF_POLICY_LINEAR)
-        builder.setPersisted(true)
-        jobScheduler.schedule(builder.build())
     }
 }
diff --git a/app/src/main/java/ch/dissem/apps/abit/util/Observable.kt b/app/src/main/java/ch/dissem/apps/abit/util/Observable.kt
index e384fde..36692ec 100644
--- a/app/src/main/java/ch/dissem/apps/abit/util/Observable.kt
+++ b/app/src/main/java/ch/dissem/apps/abit/util/Observable.kt
@@ -8,11 +8,11 @@ import kotlin.properties.Delegates
 class Observable<T>(value: T) {
     private val observers = mutableMapOf<Any, (T) -> Unit>()
 
-    var value: T by Delegates.observable(value, { _, old, new ->
+    var value: T by Delegates.observable(value) { _, old, new ->
         if (old != new) {
             observers.values.forEach { it.invoke(new) }
         }
-    })
+    }
 
     /**
      * The key will make sure the observer can easily be removed. Usually the key should be either
diff --git a/app/src/main/java/ch/dissem/apps/abit/util/Preferences.kt b/app/src/main/java/ch/dissem/apps/abit/util/Preferences.kt
index 44265b1..558a9ea 100644
--- a/app/src/main/java/ch/dissem/apps/abit/util/Preferences.kt
+++ b/app/src/main/java/ch/dissem/apps/abit/util/Preferences.kt
@@ -17,127 +17,63 @@
 package ch.dissem.apps.abit.util
 
 import android.content.Context
-import ch.dissem.apps.abit.R
-import ch.dissem.apps.abit.notification.ErrorNotification
+import android.content.Intent
+import android.content.IntentFilter
+import android.os.BatteryManager
+import android.os.Build
 import ch.dissem.apps.abit.util.Constants.PREFERENCE_EMULATE_CONVERSATIONS
-import ch.dissem.apps.abit.util.Constants.PREFERENCE_FULL_NODE
+import ch.dissem.apps.abit.util.Constants.PREFERENCE_ONLINE
 import ch.dissem.apps.abit.util.Constants.PREFERENCE_REQUEST_ACK
 import ch.dissem.apps.abit.util.Constants.PREFERENCE_REQUIRE_CHARGING
-import ch.dissem.apps.abit.util.Constants.PREFERENCE_SYNC_TIMEOUT
-import ch.dissem.apps.abit.util.Constants.PREFERENCE_TRUSTED_NODE
 import ch.dissem.apps.abit.util.Constants.PREFERENCE_WIFI_ONLY
 import org.jetbrains.anko.batteryManager
 import org.jetbrains.anko.connectivityManager
 import org.jetbrains.anko.defaultSharedPreferences
 import org.slf4j.LoggerFactory
 import java.io.File
-import java.io.IOException
-import java.net.InetAddress
-import android.os.BatteryManager
-import android.content.Intent
-import android.content.IntentFilter
-import android.os.Build
+import java.lang.ref.WeakReference
 
 
+val Context.preferences get() = Preferences.getInstance(this)
+
 /**
  * @author Christian Basler
  */
-object Preferences {
+class Preferences internal constructor(private val ctx: Context) {
     private val LOG = LoggerFactory.getLogger(Preferences::class.java)
 
-    fun useTrustedNode(ctx: Context): Boolean {
-        val trustedNode = getPreference(ctx, PREFERENCE_TRUSTED_NODE) ?: return false
-        return trustedNode.trim { it <= ' ' }.isNotEmpty()
-    }
+    val connectionAllowed get() = isAllowedForWiFi && isAllowedForCharging
 
-    /**
-     * Warning, this method might do a network call and therefore can't be called from
-     * the UI thread.
-     */
-    @Throws(IOException::class)
-    fun getTrustedNode(ctx: Context): InetAddress? {
-        var trustedNode: String = getPreference(ctx, PREFERENCE_TRUSTED_NODE) ?: return null
-        trustedNode = trustedNode.trim { it <= ' ' }
-        if (trustedNode.isEmpty()) return null
+    private val isAllowedForWiFi get() = !wifiOnly || !ctx.connectivityManager.isActiveNetworkMetered
 
-        if (trustedNode.matches("^(?![0-9a-fA-F]*:[0-9a-fA-F]*:).*(:[0-9]+)$".toRegex())) {
-            val index = trustedNode.lastIndexOf(':')
-            trustedNode = trustedNode.substring(0, index)
+    private val isAllowedForCharging get() = !requireCharging || isCharging
+
+    private val isCharging
+        get() = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+            ctx.batteryManager.isCharging
+        } else {
+            val intent = ctx.registerReceiver(null, IntentFilter(Intent.ACTION_BATTERY_CHANGED))
+            val status = intent.getIntExtra(BatteryManager.EXTRA_STATUS, -1)
+            status == BatteryManager.BATTERY_STATUS_CHARGING || status == BatteryManager.BATTERY_STATUS_FULL
         }
-        return InetAddress.getByName(trustedNode)
-    }
 
-    fun getTrustedNodePort(ctx: Context): Int {
-        var trustedNode: String = getPreference(ctx, PREFERENCE_TRUSTED_NODE) ?: return 8444
-        trustedNode = trustedNode.trim { it <= ' ' }
-
-        if (trustedNode.matches("^(?![0-9a-fA-F]*:[0-9a-fA-F]*:).*(:[0-9]+)$".toRegex())) {
-            val index = trustedNode.lastIndexOf(':')
-            val portString = trustedNode.substring(index + 1)
-            try {
-                return Integer.parseInt(portString)
-            } catch (e: NumberFormatException) {
-                ErrorNotification(ctx)
-                    .setError(R.string.error_invalid_sync_port, portString)
-                    .show()
-            }
+    var wifiOnly
+        get() = ctx.defaultSharedPreferences.getBoolean(PREFERENCE_WIFI_ONLY, true)
+        set(value) {
+            ctx.defaultSharedPreferences.edit()
+                .putBoolean(PREFERENCE_WIFI_ONLY, value)
+                .apply()
         }
-        return 8444
-    }
 
-    fun getTimeoutInSeconds(ctx: Context): Long = getPreference(ctx, PREFERENCE_SYNC_TIMEOUT)?.toLong() ?: 120
+    val requireCharging get() = ctx.defaultSharedPreferences.getBoolean(PREFERENCE_REQUIRE_CHARGING, true)
 
-    private fun getPreference(ctx: Context, name: String): String? = ctx.defaultSharedPreferences.getString(name, null)
+    val emulateConversations get() = ctx.defaultSharedPreferences.getBoolean(PREFERENCE_EMULATE_CONVERSATIONS, true)
 
-    fun isConnectionAllowed(ctx: Context) = isAllowedForWiFi(ctx) && isAllowedForCharging(ctx)
+    val exportDirectory by lazy { File(ctx.filesDir, "exports") }
 
-    private fun isAllowedForWiFi(ctx: Context) = !isWifiOnly(ctx) || !ctx.connectivityManager.isActiveNetworkMetered
+    val requestAcknowledgements = ctx.defaultSharedPreferences.getBoolean(PREFERENCE_REQUEST_ACK, true)
 
-    private fun isAllowedForCharging(ctx: Context) = !requireCharging(ctx) || isCharging(ctx)
-
-    private fun isCharging(ctx: Context) = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-        ctx.batteryManager.isCharging
-    } else {
-        val intent = ctx.registerReceiver(null, IntentFilter(Intent.ACTION_BATTERY_CHANGED))
-        val status = intent.getIntExtra(BatteryManager.EXTRA_STATUS, -1)
-        status == BatteryManager.BATTERY_STATUS_CHARGING || status == BatteryManager.BATTERY_STATUS_FULL
-    }
-
-    fun isWifiOnly(ctx: Context) = ctx.defaultSharedPreferences.getBoolean(PREFERENCE_WIFI_ONLY, true)
-
-    fun setWifiOnly(ctx: Context, status: Boolean) {
-        ctx.defaultSharedPreferences.edit()
-            .putBoolean(PREFERENCE_WIFI_ONLY, status)
-            .apply()
-    }
-
-    fun requireCharging(ctx: Context) = ctx.defaultSharedPreferences.getBoolean(PREFERENCE_REQUIRE_CHARGING, true)
-
-    fun setRequireCharging(ctx: Context, status: Boolean) {
-        ctx.defaultSharedPreferences.edit()
-            .putBoolean(PREFERENCE_REQUIRE_CHARGING, status)
-            .apply()
-    }
-
-    fun isEmulateConversations(ctx: Context) =
-        ctx.defaultSharedPreferences.getBoolean(PREFERENCE_EMULATE_CONVERSATIONS, true)
-
-
-    fun isFullNodeActive(ctx: Context) =
-        ctx.defaultSharedPreferences.getBoolean(PREFERENCE_FULL_NODE, false)
-
-    fun setFullNodeActive(ctx: Context, status: Boolean) {
-        ctx.defaultSharedPreferences.edit()
-            .putBoolean(PREFERENCE_FULL_NODE, status)
-            .apply()
-    }
-
-    fun getExportDirectory(ctx: Context) = File(ctx.filesDir, "exports")
-
-    fun requestAcknowledgements(ctx: Context) = ctx.defaultSharedPreferences.getBoolean(PREFERENCE_REQUEST_ACK, true)
-
-    fun cleanupExportDirectory(ctx: Context) {
-        val exportDirectory = getExportDirectory(ctx)
+    fun cleanupExportDirectory() {
         if (exportDirectory.exists()) {
             exportDirectory.listFiles().forEach { file ->
                 try {
@@ -150,4 +86,30 @@ object Preferences {
             }
         }
     }
+
+    var online
+        get() = ctx.defaultSharedPreferences.getBoolean(PREFERENCE_ONLINE, true)
+        set(value) {
+            ctx.defaultSharedPreferences.edit()
+                .putBoolean(PREFERENCE_ONLINE, value)
+                .apply()
+            if (value) {
+                ctx.network.enableNode(true)
+            } else {
+                ctx.network.disableNode()
+            }
+        }
+
+    companion object {
+        private var instance: WeakReference<Preferences>? = null
+
+        internal fun getInstance(ctx: Context): Preferences {
+            var prefs = instance?.get()
+            if (prefs == null) {
+                prefs = Preferences(ctx.applicationContext)
+                instance = WeakReference(prefs)
+            }
+            return prefs
+        }
+    }
 }
diff --git a/app/src/main/res/drawable/material_showcase_button_bg.xml b/app/src/main/res/drawable/material_showcase_button_bg.xml
deleted file mode 100644
index 4df0f4b..0000000
--- a/app/src/main/res/drawable/material_showcase_button_bg.xml
+++ /dev/null
@@ -1,9 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<ripple xmlns:android="http://schemas.android.com/apk/res/android"
-        android:color="#ffffff">
-
-    <item
-            android:id="@android:id/mask"
-            android:drawable="@android:color/white"/>
-
-</ripple>
\ No newline at end of file
diff --git a/app/src/main/res/values-ar/strings.xml b/app/src/main/res/values-ar/strings.xml
index 7ea90b4..bdb2fc2 100644
--- a/app/src/main/res/values-ar/strings.xml
+++ b/app/src/main/res/values-ar/strings.xml
@@ -30,8 +30,6 @@
     <string name="reply">رد</string>
     <string name="delete">حذف</string>
     <string name="empty_trash">أفرغ المهملات</string>
-    <string name="trusted_node">عقدة موثوقة</string>
-    <string name="trusted_node_summary">استخدام العقدة في التزامن</string>
     <string name="write_message">كتابة رسالة</string>
     <string name="full_node">عقدة كاملة</string>
     <string name="send">إرسال</string>
@@ -51,15 +49,10 @@
     <string name="mark_unread">حدد كمقروء</string>
     <string name="archive">أرشيف</string>
     <string name="stream_number">بث #%d</string>
-    <string name="sync_timeout">انتهاء مهلة التزامن</string>
-    <string name="sync_timeout_summary">مهلة الإتصال بالثواني</string>
     <string name="proof_of_work_text_n" tools:ignore="PluralsCandidate">جاري إثبات العمل لإرسال الرسالة (%1$d في قائمة الانتظار)</string>
-    <string name="error_invalid_sync_port">إعدادات منفذ التزامن غير صالحة</string>
     <string name="compose_body_hint">كتابة رسالة</string>
     <string name="contacts_and_subscriptions">جهات اتصال</string>
     <string name="subscribed">تم الاشتراك</string>
-    <string name="server_pow">خادم إثبات العمل</string>
-    <string name="server_pow_summary">عقدة موثوقة تقوم بإثبات العمل</string>
     <string name="full_node_warning">تشغيل عقدة Bitmessage كاملة يستهلك الكثير من البيانات، مما قد يكون مكلفًا لبيانات الهاتف، هل أنت متأكد أنك تريد تشغيل عقدة كاملة؟</string>
     <string name="about">عن Abit</string>
     <string name="about_summary">التبعيات مفتوحة المصدر.</string>
diff --git a/app/src/main/res/values-de/strings.xml b/app/src/main/res/values-de/strings.xml
index d300a58..0c68008 100644
--- a/app/src/main/res/values-de/strings.xml
+++ b/app/src/main/res/values-de/strings.xml
@@ -35,10 +35,6 @@
     <string name="archive">Archiv</string>
     <string name="empty_trash">Papierkorb leeren</string>
     <string name="stream_number">Stream %d</string>
-    <string name="trusted_node">Vertrauenswürdiger Knoten</string>
-    <string name="trusted_node_summary">Diese Adresse wird für die Synchronisation verwendet</string>
-    <string name="sync_timeout">Zeitbeschränkung der Synchronisierung</string>
-    <string name="sync_timeout_summary">Timeout in Sekunden</string>
     <string name="write_message">Schreiben</string>
     <string name="full_node">Aktiver Knoten</string>
     <string name="send">Senden</string>
@@ -47,12 +43,9 @@
     <string name="proof_of_work_title">Proof of Work</string>
     <string name="proof_of_work_text_0">Arbeite am Versenden</string>
     <string name="proof_of_work_text_n">Arbeite am Versenden (%1$d in Warteschlange)</string>
-    <string name="error_invalid_sync_port">Ungültiger Port in den Synchronisationseinstellungen: %s</string>
     <string name="compose_body_hint">Nachricht schreiben</string>
     <string name="contacts_and_subscriptions">Kontakte</string>
     <string name="subscribed">Abonniert</string>
-    <string name="server_pow">Server POW</string>
-    <string name="server_pow_summary">Der vertrauenswürdige Knoten macht den Proof of Work</string>
     <string name="full_node_warning">Ein aktiver Bitmessage-Knoten muss viel hoch- und herunterladen, was auf einem mobilen Netzwerk teuer sein kann. Soll tatsächlich ein aktiver Knoten gestartet werden?</string>
     <string name="about">Über Abit</string>
     <string name="about_summary">Opensource Abhängigkeiten.</string>
@@ -139,4 +132,17 @@ Als Alternative kann in den Einstellungen ein vertrauenswürdiger Knoten konfigu
     <string name="encoding_extended">erweitert</string>
     <string name="emulate_conversations">Konversation erraten</string>
     <string name="emulate_conversations_summary">Benutze Betreff um zu erraten welche Nachrichten zusammengehören. Die Reihenfolge stimmt häufig nicht.</string>
+    <string name="online">Online</string>
+    <string name="ok">OK</string>
+    <string name="unknown">Unbekannt</string>
+    <string name="require_charging_summary">Nur verbinden wenn das Gerät geladen wird.</string>
+    <string name="require_charging">Laden erforderlich</string>
+    <string name="emulate_conversations_batch">Bestehende Nachrichten werden nach Betreff gruppiert</string>
+    <string name="emulate_conversations_initialize">Bestehende Nachrichten nach Betreff gruppieren</string>
+    <string name="preference_group_advanced">Erweitert</string>
+    <string name="preference_group_network_and_performance">Netzwerk &amp; Performanz</string>
+    <string name="preference_group_network_and_performance_summary">Feineinstellungen für Netzwerk und Protokoll-Details</string>
+    <string name="preference_group_user_experience">Verhalten</string>
+    <string name="preference_group_user_experience_summary">Ändern, wie Nachrichten dargestellt werden</string>
+    <string name="bitmessage_service_description">Hält die Verbindung zum Bitmessage-Netzwerk.</string>
 </resources>
diff --git a/app/src/main/res/values-fr/strings.xml b/app/src/main/res/values-fr/strings.xml
index 48ae83d..56bb78f 100644
--- a/app/src/main/res/values-fr/strings.xml
+++ b/app/src/main/res/values-fr/strings.xml
@@ -36,9 +36,6 @@
     <string name="mark_unread">Marquer non lu</string>
     <string name="archive">Archive</string>
     <string name="stream_number">"Flux  nº%d"</string>
-    <string name="trusted_node">Nœud de confiance</string>
-    <string name="trusted_node_summary">Cette adresse est utilisée pour la synchronisation</string>
-    <string name="sync_timeout">Limitation du temps de synchronisation</string>
     <string name="write_message">Écrire un message</string>
     <string name="full_node">Nœud actif</string>
     <string name="send">Transmission</string>
@@ -47,7 +44,6 @@
     <string name="proof_of_work_title">Preuve de travail</string>
     <string name="proof_of_work_text_0">Faire du travail pour envoyer la message</string>
     <string name="proof_of_work_text_n" tools:ignore="PluralsCandidate">Faire du travail pour envoyer la message (%1$d en file d\'attente)</string>
-    <string name="error_invalid_sync_port">Port non valide dans les paramètres de synchronisation : %s</string>
     <string name="compose_body_hint">Écrire un message</string>
     <string name="contacts_and_subscriptions">Contacts</string>
     <string name="subscribed">Souscrit</string>
@@ -94,9 +90,6 @@
     <string name="use_mobile_network">Utiliser le réseau mobile</string>
     <string name="personal_message">Message</string>
     <string name="empty_trash">Vider les ordures</string>
-    <string name="sync_timeout_summary">Délai d\'expiration en secondes</string>
-    <string name="server_pow">POW sur le serveur</string>
-    <string name="server_pow_summary">Le nœud de confiance fait la preuve de travail</string>
     <string name="share">Partager</string>
     <string name="compose_message">Composer</string>
     <string name="no_identity_warning">Veuillez réessayer dès qu\'une identité est disponible.</string>
@@ -134,4 +127,9 @@
     <string name="broadcasts">Diffusions</string>
     <string name="encoding_simple">simple</string>
     <string name="encoding_extended">étendu</string>
+    <string name="online">En ligne</string>
+    <string name="unknown">Inconnue</string>
+    <string name="require_charging">Exigence d\'une charge</string>
+    <string name="require_charging_summary">Connecter uniquement lorsque l\'appareil est branché.</string>
+    <string name="bitmessage_service_description">Garde la connexion au réseau bitmessage.</string>
 </resources>
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index bd1f3a8..313eee0 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -153,4 +153,7 @@ As an alternative you could configure a trusted node in the settings, but as of
     <string name="require_charging_summary">Only connect when device is plugged in</string>
     <string name="unknown">Unknown</string>
     <string name="ok">OK</string>
+    <string name="online">Online</string>
+    <string name="warning_low_memory">Low memory!</string>
+    <string name="bitmessage_service_description">Keeps the connection to the bitmessage network.</string>
 </resources>
diff --git a/app/src/main/res/xml/authenticator.xml b/app/src/main/res/xml/authenticator.xml
deleted file mode 100644
index 17609a0..0000000
--- a/app/src/main/res/xml/authenticator.xml
+++ /dev/null
@@ -1,6 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<account-authenticator xmlns:android="http://schemas.android.com/apk/res/android"
-    android:accountType="ch.dissem.bitmessage"
-    android:icon="@mipmap/ic_launcher"
-    android:label="@string/app_name"
-    android:smallIcon="@mipmap/ic_launcher" />
\ No newline at end of file
diff --git a/app/src/main/res/xml/preferences.xml b/app/src/main/res/xml/preferences.xml
index eeecaad..74f1510 100644
--- a/app/src/main/res/xml/preferences.xml
+++ b/app/src/main/res/xml/preferences.xml
@@ -63,35 +63,10 @@
             android:summary="@string/import_data_summary"
             android:title="@string/import_data" />
 
-        <PreferenceScreen
-            android:key="preference_experimental"
-            android:title="@string/preference_group_experimental"
-            android:summary="@string/preference_group_experimental_summary"
-            android:persistent="false">
-
-            <EditTextPreference
-                android:inputType="textUri"
-                android:key="trusted_node"
-                android:summary="@string/trusted_node_summary"
-                android:title="@string/trusted_node" />
-            <EditTextPreference
-                android:defaultValue="120"
-                android:inputType="number"
-                android:key="sync_timeout"
-                android:summary="@string/sync_timeout_summary"
-                android:title="@string/sync_timeout" />
-            <SwitchPreferenceCompat
-                android:defaultValue="false"
-                android:dependency="trusted_node"
-                android:key="server_pow"
-                android:summary="@string/server_pow_summary"
-                android:title="@string/server_pow" />
-            <Preference
-                android:key="status"
-                android:summary="@string/status_summary"
-                android:title="@string/status" />
-
-        </PreferenceScreen>
+        <Preference
+            android:key="status"
+            android:summary="@string/status_summary"
+            android:title="@string/status" />
 
     </PreferenceScreen>
 
diff --git a/app/src/main/res/xml/syncadapter.xml b/app/src/main/res/xml/syncadapter.xml
deleted file mode 100644
index c28b46b..0000000
--- a/app/src/main/res/xml/syncadapter.xml
+++ /dev/null
@@ -1,9 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<sync-swipeableMessageAdapter
-    xmlns:android="http://schemas.android.com/apk/res/android"
-    android:contentAuthority="ch.dissem.apps.abit.provider"
-    android:accountType="ch.dissem.bitmessage"
-    android:userVisible="true"
-    android:supportsUploading="true"
-    android:allowParallelSyncs="false"
-    android:isAlwaysSyncable="true"/>
diff --git a/app/src/test/java/ch/dissem/bitmessage/repository/TestBase.kt b/app/src/test/java/ch/dissem/bitmessage/repository/TestBase.kt
index 4055ac4..6a94b78 100644
--- a/app/src/test/java/ch/dissem/bitmessage/repository/TestBase.kt
+++ b/app/src/test/java/ch/dissem/bitmessage/repository/TestBase.kt
@@ -110,7 +110,7 @@ open class TestBase {
         }
 
         fun loadIdentity(address: String): BitmessageAddress {
-            val privateKey = PrivateKey.read(getResource(address + ".privkey"))
+            val privateKey = PrivateKey.read(getResource("$address.privkey"))
             val identity = BitmessageAddress(privateKey)
             Assert.assertEquals(address, identity.address)
             return identity
diff --git a/build.gradle b/build.gradle
index bf3abe2..634522a 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,5 +1,5 @@
 buildscript {
-    ext.kotlin_version = '1.2.50'
+    ext.kotlin_version = '1.2.51'
     ext.anko_version = '0.10.5'
     repositories {
         jcenter()