diff --git a/build.gradle b/build.gradle
index 2b2cacd9..c72dfe34 100644
--- a/build.gradle
+++ b/build.gradle
@@ -3,7 +3,7 @@
 apply plugin: 'com.github.ben-manes.versions'
 
 buildscript {
-    ext.kotlinVersion = '1.3.21'
+    ext.kotlinVersion = '1.3.30'
     repositories {
         google()
         jcenter()
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index 13372aef..87b738cb 100644
Binary files a/gradle/wrapper/gradle-wrapper.jar and b/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 17de17a7..51fb1c46 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,6 +1,5 @@
-#Wed Jan 03 07:06:26 CST 2018
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.3.1-all.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.2.1-all.zip
diff --git a/gradlew b/gradlew
index 9d82f789..af6708ff 100755
--- a/gradlew
+++ b/gradlew
@@ -1,4 +1,4 @@
-#!/usr/bin/env bash
+#!/usr/bin/env sh
 
 ##############################################################################
 ##
@@ -6,42 +6,6 @@
 ##
 ##############################################################################
 
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS=""
-
-APP_NAME="Gradle"
-APP_BASE_NAME=`basename "$0"`
-
-# Use the maximum available, or set MAX_FD != -1 to use that value.
-MAX_FD="maximum"
-
-warn ( ) {
-    echo "$*"
-}
-
-die ( ) {
-    echo
-    echo "$*"
-    echo
-    exit 1
-}
-
-# OS specific support (must be 'true' or 'false').
-cygwin=false
-msys=false
-darwin=false
-case "`uname`" in
-  CYGWIN* )
-    cygwin=true
-    ;;
-  Darwin* )
-    darwin=true
-    ;;
-  MINGW* )
-    msys=true
-    ;;
-esac
-
 # Attempt to set APP_HOME
 # Resolve links: $0 may be a link
 PRG="$0"
@@ -60,6 +24,46 @@ cd "`dirname \"$PRG\"`/" >/dev/null
 APP_HOME="`pwd -P`"
 cd "$SAVED" >/dev/null
 
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 # Determine the Java command to use to start the JVM.
@@ -85,7 +89,7 @@ location of your Java installation."
 fi
 
 # Increase the maximum file descriptors if we can.
-if [ "$cygwin" = "false" -a "$darwin" = "false" ] ; then
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
     MAX_FD_LIMIT=`ulimit -H -n`
     if [ $? -eq 0 ] ; then
         if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
@@ -150,11 +154,19 @@ if $cygwin ; then
     esac
 fi
 
-# Split up the JVM_OPTS And GRADLE_OPTS values into an array, following the shell quoting and substitution rules
-function splitJvmOpts() {
-    JVM_OPTS=("$@")
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
 }
-eval splitJvmOpts $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS
-JVM_OPTS[${#JVM_OPTS[*]}]="-Dorg.gradle.appname=$APP_BASE_NAME"
+APP_ARGS=$(save "$@")
 
-exec "$JAVACMD" "${JVM_OPTS[@]}" -classpath "$CLASSPATH" org.gradle.wrapper.GradleWrapperMain "$@"
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
+if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
+  cd "$(dirname "$0")"
+fi
+
+exec "$JAVACMD" "$@"
diff --git a/gradlew.bat b/gradlew.bat
index aec99730..0f8d5937 100644
--- a/gradlew.bat
+++ b/gradlew.bat
@@ -8,14 +8,14 @@
 @rem Set local scope for the variables with windows NT shell
 if "%OS%"=="Windows_NT" setlocal
 
-@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=
-
 set DIRNAME=%~dp0
 if "%DIRNAME%" == "" set DIRNAME=.
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m"
+
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
@@ -46,10 +46,9 @@ echo location of your Java installation.
 goto fail
 
 :init
-@rem Get command-line arguments, handling Windowz variants
+@rem Get command-line arguments, handling Windows variants
 
 if not "%OS%" == "Windows_NT" goto win9xME_args
-if "%@eval[2+2]" == "4" goto 4NT_args
 
 :win9xME_args
 @rem Slurp the command line arguments.
@@ -60,11 +59,6 @@ set _SKIP=2
 if "x%~1" == "x" goto execute
 
 set CMD_LINE_ARGS=%*
-goto execute
-
-:4NT_args
-@rem Get arguments from the 4NT Shell from JP Software
-set CMD_LINE_ARGS=%$
 
 :execute
 @rem Setup the command line
diff --git a/mobile/build.gradle b/mobile/build.gradle
index 00d48a1e..553d9674 100644
--- a/mobile/build.gradle
+++ b/mobile/build.gradle
@@ -41,6 +41,7 @@ android {
     }
     dataBinding.enabled = true
     flavorDimensions("freedom")
+    packagingOptions.exclude '**/*.kotlin_*'
     productFlavors {
         fdroid {
             dimension "freedom"
@@ -81,14 +82,14 @@ dependencies {
     implementation "androidx.room:room-ktx:$roomVersion"
     implementation 'com.android.billingclient:billing:1.2.2'
     implementation 'com.github.luongvo:BadgeView:1.1.5'
-    implementation 'com.github.topjohnwu.libsu:core:2.3.3'
+    implementation 'com.github.topjohnwu.libsu:core:2.4.0'
     implementation 'com.google.android.material:material:1.0.0'
     implementation 'com.jakewharton.timber:timber:4.7.1'
     implementation 'com.linkedin.dexmaker:dexmaker:2.25.0'
     implementation 'com.takisoft.preferencex:preferencex-simplemenu:1.0.0'
     implementation 'net.glxn.qrgen:android:2.0'
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlinVersion"
-    implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.1.1'
+    implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.2.0'
     for (dep in aux) {
         freedomImplementation dep
         googleImplementation dep
diff --git a/mobile/lint.xml b/mobile/lint.xml
index 06e04731..78700082 100644
--- a/mobile/lint.xml
+++ b/mobile/lint.xml
@@ -3,5 +3,5 @@
     <issue id="InvalidPackage">
         <ignore regexp="org.mockito.*" />
     </issue>
-    <issue id="MissingTranslation" severity="informational" />
+    <issue id="MissingTranslation" severity="ignore" />
 </lint>
diff --git a/mobile/src/main/java/be/mygod/vpnhotspot/client/ClientsFragment.kt b/mobile/src/main/java/be/mygod/vpnhotspot/client/ClientsFragment.kt
index 685439ef..de9d3b51 100644
--- a/mobile/src/main/java/be/mygod/vpnhotspot/client/ClientsFragment.kt
+++ b/mobile/src/main/java/be/mygod/vpnhotspot/client/ClientsFragment.kt
@@ -36,18 +36,15 @@ import be.mygod.vpnhotspot.room.AppDatabase
 import be.mygod.vpnhotspot.room.ClientStats
 import be.mygod.vpnhotspot.room.TrafficRecord
 import be.mygod.vpnhotspot.room.macToString
-import be.mygod.vpnhotspot.util.MainScope
 import be.mygod.vpnhotspot.util.SpanFormatter
 import be.mygod.vpnhotspot.util.computeIfAbsentCompat
 import be.mygod.vpnhotspot.util.toPluralInt
 import be.mygod.vpnhotspot.widget.SmartSnackbar
 import kotlinx.android.parcel.Parcelize
-import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.GlobalScope
-import kotlinx.coroutines.launch
+import kotlinx.coroutines.*
 import java.text.NumberFormat
 
-class ClientsFragment : Fragment(), MainScope by MainScope.Supervisor() {
+class ClientsFragment : Fragment() {
     @Parcelize
     data class NicknameArg(val mac: Long, val nickname: CharSequence) : Parcelable
     class NicknameDialogFragment : AlertDialogFragment<NicknameArg, Empty>() {
@@ -140,7 +137,9 @@ class ClientsFragment : Fragment(), MainScope by MainScope.Supervisor() {
                     val wasWorking = TrafficRecorder.isWorking(client.mac)
                     client.obtainRecord().apply {
                         blocked = !blocked
-                        launch(Dispatchers.Unconfined) { AppDatabase.instance.clientRecordDao.update(this@apply) }
+                        GlobalScope.launch(Dispatchers.Unconfined) {
+                            AppDatabase.instance.clientRecordDao.update(this@apply)
+                        }
                     }
                     IpNeighbourMonitor.instance?.flush()
                     if (!wasWorking && item.itemId == R.id.block) {
@@ -150,7 +149,7 @@ class ClientsFragment : Fragment(), MainScope by MainScope.Supervisor() {
                 }
                 R.id.stats -> {
                     binding.client?.let { client ->
-                        launch(Dispatchers.Unconfined) {
+                        scope.launch {
                             StatsDialogFragment().withArg(StatsArg(
                                     client.title.value ?: return@launch,
                                     AppDatabase.instance.trafficRecordDao.queryStats(client.mac)
@@ -205,6 +204,7 @@ class ClientsFragment : Fragment(), MainScope by MainScope.Supervisor() {
         }
     }
 
+    private val scope = MainScope() + Dispatchers.Unconfined
     private lateinit var binding: FragmentClientsBinding
     private val adapter = ClientAdapter()
     private var rates = HashMap<Pair<String, Long>, TrafficRate>()
@@ -237,7 +237,7 @@ class ClientsFragment : Fragment(), MainScope by MainScope.Supervisor() {
     }
 
     override fun onDestroy() {
-        job.cancel()
+        scope.cancel()
         super.onDestroy()
     }
 }
diff --git a/mobile/src/main/java/be/mygod/vpnhotspot/manage/RepeaterManager.kt b/mobile/src/main/java/be/mygod/vpnhotspot/manage/RepeaterManager.kt
index f8c38527..f23bb7fd 100644
--- a/mobile/src/main/java/be/mygod/vpnhotspot/manage/RepeaterManager.kt
+++ b/mobile/src/main/java/be/mygod/vpnhotspot/manage/RepeaterManager.kt
@@ -219,6 +219,6 @@ class RepeaterManager(private val parent: TetheringFragment) : Manager(), Servic
             }
             holder.config = null
         }
-        RepeaterService.operatingChannel = config.apChannel
+        if (Build.VERSION.SDK_INT >= 23) RepeaterService.operatingChannel = config.apChannel
     }
 }
diff --git a/mobile/src/main/java/be/mygod/vpnhotspot/manage/TetherManager.kt b/mobile/src/main/java/be/mygod/vpnhotspot/manage/TetherManager.kt
index f1a0a1ab..3ca6a172 100644
--- a/mobile/src/main/java/be/mygod/vpnhotspot/manage/TetherManager.kt
+++ b/mobile/src/main/java/be/mygod/vpnhotspot/manage/TetherManager.kt
@@ -163,7 +163,7 @@ sealed class TetherManager(protected val parent: TetheringFragment) : Manager(),
         override val type get() = VIEW_TYPE_BLUETOOTH
         override val isStarted get() = tethering.active == true
 
-        override fun onException() = ManageBar.start(parent.requireContext())
+        override fun onException() = ManageBar.start(parent.context ?: app)
 
         override fun start() = BluetoothTethering.start(this)
         override fun stop() {
diff --git a/mobile/src/main/java/be/mygod/vpnhotspot/manage/TetheringFragment.kt b/mobile/src/main/java/be/mygod/vpnhotspot/manage/TetheringFragment.kt
index 65161c04..46fb8caf 100644
--- a/mobile/src/main/java/be/mygod/vpnhotspot/manage/TetheringFragment.kt
+++ b/mobile/src/main/java/be/mygod/vpnhotspot/manage/TetheringFragment.kt
@@ -105,7 +105,7 @@ class TetheringFragment : Fragment(), ServiceConnection, Toolbar.OnMenuItemClick
     }
 
     private fun updateMonitorList(canMonitor: List<String> = emptyList()) {
-        val item = requireActivity().toolbar.menu.findItem(R.id.monitor) ?: return  // assuming no longer foreground
+        val item = activity?.toolbar?.menu?.findItem(R.id.monitor) ?: return    // assuming no longer foreground
         item.isNotGone = canMonitor.isNotEmpty()
         item.subMenu.apply {
             clear()
diff --git a/mobile/src/main/java/be/mygod/vpnhotspot/net/wifi/WifiApManager.kt b/mobile/src/main/java/be/mygod/vpnhotspot/net/wifi/WifiApManager.kt
index 7d9740ac..ca81b80c 100644
--- a/mobile/src/main/java/be/mygod/vpnhotspot/net/wifi/WifiApManager.kt
+++ b/mobile/src/main/java/be/mygod/vpnhotspot/net/wifi/WifiApManager.kt
@@ -13,7 +13,9 @@ object WifiApManager {
     var configuration: WifiConfiguration
         get() = getWifiApConfiguration.invoke(app.wifi) as WifiConfiguration
         set(value) {
-            if (setWifiApConfiguration.invoke(app.wifi, value) as? Boolean != true) throw IllegalArgumentException()
+            if (setWifiApConfiguration.invoke(app.wifi, value) as? Boolean != true) {
+                throw IllegalArgumentException("setWifiApConfiguration failed")
+            }
         }
 
     private val setWifiApEnabled by lazy {
diff --git a/mobile/src/main/java/be/mygod/vpnhotspot/net/wifi/configuration/WifiApDialogFragment.kt b/mobile/src/main/java/be/mygod/vpnhotspot/net/wifi/configuration/WifiApDialogFragment.kt
index f0af651c..c08b6b34 100644
--- a/mobile/src/main/java/be/mygod/vpnhotspot/net/wifi/configuration/WifiApDialogFragment.kt
+++ b/mobile/src/main/java/be/mygod/vpnhotspot/net/wifi/configuration/WifiApDialogFragment.kt
@@ -24,6 +24,7 @@ import be.mygod.vpnhotspot.RepeaterService
 import be.mygod.vpnhotspot.util.QRCodeDialog
 import be.mygod.vpnhotspot.util.toByteArray
 import be.mygod.vpnhotspot.util.toParcelable
+import be.mygod.vpnhotspot.widget.SmartSnackbar
 import kotlinx.android.parcel.Parcelize
 import kotlinx.android.synthetic.main.dialog_wifi_ap.view.*
 import java.lang.IllegalStateException
@@ -75,10 +76,11 @@ class WifiApDialogFragment : AlertDialogFragment<WifiApDialogFragment.Arg, WifiA
     private lateinit var dialogView: View
     private lateinit var bandOptions: MutableList<BandOption>
     private var started = false
+    private val selectedSecurity get() =
+        if (arg.p2pMode) WifiConfiguration.KeyMgmt.WPA_PSK else dialogView.security.selectedItemPosition
     override val ret get() = Arg(WifiConfiguration().apply {
         SSID = dialogView.ssid.text.toString()
-        allowedKeyManagement.set(
-                if (arg.p2pMode) WifiConfiguration.KeyMgmt.WPA_PSK else dialogView.security.selectedItemPosition)
+        allowedKeyManagement.set(selectedSecurity)
         allowedAuthAlgorithms.set(WifiConfiguration.AuthAlgorithm.OPEN)
         if (dialogView.password.length() != 0) preSharedKey = dialogView.password.text.toString()
         if (Build.VERSION.SDK_INT >= 23) {
@@ -132,7 +134,7 @@ class WifiApDialogFragment : AlertDialogFragment<WifiApDialogFragment.Arg, WifiA
             if (Build.VERSION.SDK_INT < 23) {
                 setSelection(bandOptions.indexOfFirst { it.apChannel == RepeaterService.operatingChannel })
             }
-        }
+        } else dialogView.band_wrapper.isGone = true
         populateFromConfiguration(arg.configuration)
     }
 
@@ -160,7 +162,7 @@ class WifiApDialogFragment : AlertDialogFragment<WifiApDialogFragment.Arg, WifiA
         if (!started) return
         val ssidValid = dialogView.ssid.length() != 0 &&
                 Charset.forName("UTF-8").encode(dialogView.ssid.text.toString()).limit() <= 32
-        val passwordValid = when (dialogView.security.selectedItemPosition) {
+        val passwordValid = when (selectedSecurity) {
             WifiConfiguration.KeyMgmt.WPA_PSK, WPA2_PSK -> dialogView.password.length() >= 8
             else -> true    // do not try to validate
         }
@@ -181,12 +183,15 @@ class WifiApDialogFragment : AlertDialogFragment<WifiApDialogFragment.Arg, WifiA
                         Base64.encodeToString(ret.configuration.toByteArray(), BASE64_FLAGS)))
                 true
             }
-            android.R.id.paste -> {
+            android.R.id.paste -> try {
                 app.clipboard.primaryClip?.getItemAt(0)?.text?.apply {
                     Base64.decode(toString(), BASE64_FLAGS).toParcelable<WifiConfiguration>()
                             ?.let { populateFromConfiguration(it) }
                 }
                 true
+            } catch (e: IllegalArgumentException) {
+                SmartSnackbar.make(e).show()
+                false
             }
             R.id.share_qr -> {
                 QRCodeDialog().withArg(ret.configuration.toQRString())
@@ -199,7 +204,7 @@ class WifiApDialogFragment : AlertDialogFragment<WifiApDialogFragment.Arg, WifiA
 
     override fun onClick(dialog: DialogInterface?, which: Int) {
         super.onClick(dialog, which)
-        if (Build.VERSION.SDK_INT < 23 && which == DialogInterface.BUTTON_POSITIVE) {
+        if (Build.VERSION.SDK_INT < 23 && arg.p2pMode && which == DialogInterface.BUTTON_POSITIVE) {
             RepeaterService.operatingChannel = (dialogView.band.selectedItem as BandOption).apChannel
         }
     }
diff --git a/mobile/src/main/java/be/mygod/vpnhotspot/util/MainScope.kt b/mobile/src/main/java/be/mygod/vpnhotspot/util/MainScope.kt
deleted file mode 100644
index 01760f85..00000000
--- a/mobile/src/main/java/be/mygod/vpnhotspot/util/MainScope.kt
+++ /dev/null
@@ -1,14 +0,0 @@
-package be.mygod.vpnhotspot.util
-
-import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.Job
-import kotlinx.coroutines.SupervisorJob
-
-interface MainScope : CoroutineScope {
-    class Supervisor : MainScope {
-        override val job = SupervisorJob()
-    }
-    val job: Job
-    override val coroutineContext get() = Dispatchers.Main + job
-}
diff --git a/mobile/src/main/res/values-ru/strings.xml b/mobile/src/main/res/values-ru/strings.xml
index ad690c45..3977c189 100644
--- a/mobile/src/main/res/values-ru/strings.xml
+++ b/mobile/src/main/res/values-ru/strings.xml
@@ -11,6 +11,7 @@
     <string name="repeater_p2p_unavailable">Wi-Fi директ недоступен, пожалуйста включите Wi-Fi</string>
     <string name="repeater_create_group_failure">Не удалось создать группу P2P (причина: %s)</string>
     <string name="repeater_remove_group_failure">Не удалось удалить группу P2P (причина: %s)</string>
+    <string name="repeater_remove_old_group_failure">Не удалось удалить старую группу P2P (причина:%s)</string>
 
     <string name="repeater_failure_reason_error">внутренняя ошибка</string>
     <string name="repeater_failure_reason_p2p_unsupported">Wi-Fi напрямую не поддерживается</string>
@@ -31,12 +32,15 @@
     <string name="clients_popup_block_service_inactive">Включите службу для этого интерфейса, чтобы заблокировать клиента.</string>
     <string name="clients_popup_unblock">Разблокировать</string>
     <string name="clients_popup_stats">Статистика…</string>
+    <string name="clients_mac_lookup_unexpected_error">Сервер вернул ошибку для %1$s: %2$s</string>
     <string name="clients_nickname_title">Никнэйм  для %s</string>
+    <string name="clients_nickname_set_to_vendor">Имя вендора</string>
     <string name="clients_stats_title">Статистика для %s</string>
 
 
     <string name="notification_tethering_title">VPN-модем активен</string>
     <string name="notification_channel_tethering">VPN модемная служба</string>
+    <string name="notification_interfaces_inactive">Неактивных: %s</string>
 
     <string name="failure_reason_unknown">Неизвестно #%d</string>
     <string name="exception_interface_not_found">Ошибка: Нисходящий интерфейс не найден</string>
@@ -55,7 +59,7 @@
 
     <!-- Based on: https://github.com/PrivacyApps/donations/blob/747d36a18433c7e9329691054122a8ad337a62d2/Donations/src/main/res/values-ru/donations__strings.xml -->
     <string name="donations__button_close">Закрыть</string>
-    <string name="donations__description">Считаете это приложение полезным?\\nПоддержите его разработку, отправив пожертвование разработчику!</string>
+    <string name="donations__description">Считаете это приложение полезным?\nПоддержите его разработку, отправив пожертвование разработчику!</string>
     <string name="donations__google_android_market">Google Play Store</string>
     <string name="donations__google_android_market_not_supported_title">In-App пожертвования не поддерживаются.</string>
     <string name="donations__google_android_market_not_supported">Пожертвования через приложение не поддерживаются. Google Play Store установлен правильно?</string>