diff --git a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/OmnipodDashBleManagerImpl.kt b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/OmnipodDashBleManagerImpl.kt
index aa87822628..6357672cc9 100644
--- a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/OmnipodDashBleManagerImpl.kt
+++ b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/OmnipodDashBleManagerImpl.kt
@@ -7,22 +7,24 @@ import android.bluetooth.BluetoothProfile
 import android.content.Context
 import info.nightscout.androidaps.logging.AAPSLogger
 import info.nightscout.androidaps.logging.LTag
-import info.nightscout.androidaps.plugins.pump.omnipod.dash.BuildConfig
 import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.callbacks.BleCommCallbacks
 import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.command.BleCommandHello
+import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.endecrypt.EnDecrypt
 import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.exceptions.*
 import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.io.BleIO
 import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.io.CharacteristicType
 import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.message.MessageIO
 import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.pair.LTKExchanger
 import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.scan.PodScanner
+import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.session.EapSqn
+import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.session.Session
 import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.session.SessionEstablisher
+import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.session.SessionKeys
 import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.status.ConnectionStatus
 import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.event.PodEvent
 import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.pod.command.base.Command
 import info.nightscout.androidaps.utils.extensions.toHex
 import io.reactivex.Observable
-import org.apache.commons.lang3.NotImplementedException
 import java.util.concurrent.BlockingQueue
 import java.util.concurrent.LinkedBlockingDeque
 import java.util.concurrent.TimeoutException
@@ -38,6 +40,8 @@ class OmnipodDashBleManagerImpl @Inject constructor(
     private val bluetoothManager: BluetoothManager =
         context.getSystemService(Context.BLUETOOTH_SERVICE) as BluetoothManager
     private val bluetoothAdapter: BluetoothAdapter = bluetoothManager.adapter
+    private var sessionKeys: SessionKeys? = null
+    private var msgIO: MessageIO? = null
 
     @Throws(
         FailedToConnectException::class,
@@ -60,12 +64,8 @@ class OmnipodDashBleManagerImpl @Inject constructor(
             )
         val bleCommCallbacks = BleCommCallbacks(aapsLogger, incomingPackets)
         aapsLogger.debug(LTag.PUMPBTCOMM, "Connecting to $podAddress")
-        var autoConnect = true
-        if (BuildConfig.DEBUG) {
-            autoConnect = false
-            // TODO: remove this in the future
-            // it's easier to start testing from scratch on each run.
-        }
+        val autoConnect = false // TODO: check what to use here
+
         val gatt = podDevice.connectGatt(context, autoConnect, bleCommCallbacks, BluetoothDevice.TRANSPORT_LE)
         bleCommCallbacks.waitForConnection(CONNECT_TIMEOUT_MS)
         val connectionState = bluetoothManager.getConnectionState(podDevice, BluetoothProfile.GATT)
@@ -81,9 +81,39 @@ class OmnipodDashBleManagerImpl @Inject constructor(
         return bleIO
     }
 
-    override fun sendCommand(cmd: Command): Observable<PodEvent> {
-        // TODO
-        return Observable.error(NotImplementedException("sendCommand is not yet implemented"))
+    override fun sendCommand(cmd: Command): Observable<PodEvent> = Observable.create { emitter ->
+        try {
+            val keys = sessionKeys
+            val mIO = msgIO
+            if (keys == null || mIO == null) {
+                //TODO handle reconnects
+                throw Exception("Not connected")
+            }
+            emitter.onNext(PodEvent.CommandSending(cmd))
+            // TODO switch to RX
+            emitter.onNext(PodEvent.CommandSent(cmd))
+
+            val enDecrypt = EnDecrypt(
+                aapsLogger,
+                keys.nonce,
+                keys.ck,
+            )
+
+            val session = Session(
+                aapsLogger = aapsLogger,
+                msgIO = mIO,
+                myId = Id.fromInt(CONTROLLER_ID),
+                podId = Id.fromInt(CONTROLLER_ID).increment(),
+                sessionKeys = keys,
+                enDecrypt = enDecrypt
+            )
+            val response = session.sendCommand(cmd)
+            emitter.onNext(PodEvent.ResponseReceived(response))
+
+            emitter.onComplete()
+        } catch (ex: Exception) {
+            emitter.tryOnError(ex)
+        }
     }
 
     override fun getStatus(): ConnectionStatus {
@@ -107,7 +137,6 @@ class OmnipodDashBleManagerImpl @Inject constructor(
         //  emit PodEvent.AlreadyConnected, complete the observable and return from this method
 
         try {
-            // TODO: this is wrong and I know it
             aapsLogger.info(LTag.PUMPBTCOMM, "starting new pod activation")
 
             val podScanner = PodScanner(aapsLogger, bluetoothAdapter)
@@ -123,24 +152,30 @@ class OmnipodDashBleManagerImpl @Inject constructor(
             val bleIO = connect(podAddress)
             emitter.onNext(PodEvent.BluetoothConnected(podAddress))
 
-            val msgIO = MessageIO(aapsLogger, bleIO)
-            val ltkExchanger = LTKExchanger(aapsLogger, msgIO)
+            val mIO = MessageIO(aapsLogger, bleIO)
+            val myId = Id.fromInt(CONTROLLER_ID)
+            val podId = myId.increment()
+
+            val ltkExchanger = LTKExchanger(aapsLogger, mIO)
 
             emitter.onNext(PodEvent.Pairing)
 
             val ltk = ltkExchanger.negotiateLTK()
 
-            aapsLogger.info(LTag.PUMPCOMM, "Got LTK: ${ltk.ltk.toHex()}")
-
             emitter.onNext(PodEvent.EstablishingSession)
 
-            val eapAkaExchanger = SessionEstablisher(aapsLogger, msgIO, ltk)
-            val sessionKeys = eapAkaExchanger.negotiateSessionKeys()
-            aapsLogger.info(LTag.PUMPCOMM, "CK: ${sessionKeys.ck.toHex()}")
-            aapsLogger.info(LTag.PUMPCOMM, "noncePrefix: ${sessionKeys.noncePrefix.toHex()}")
-            aapsLogger.info(LTag.PUMPCOMM, "SQN: ${sessionKeys.sqn.toHex()}")
+            val eapSqn = EapSqn(1)
+            aapsLogger.info(LTag.PUMPCOMM, "Got LTK: ${ltk.ltk.toHex()}")
+            val eapAkaExchanger = SessionEstablisher(aapsLogger, mIO, ltk, eapSqn)
+            val keys = eapAkaExchanger.negotiateSessionKeys()
+            aapsLogger.info(LTag.PUMPCOMM, "CK: ${keys.ck.toHex()}")
+            aapsLogger.info(LTag.PUMPCOMM, "msgSequenceNumber: ${keys.msgSequenceNumber}")
+            aapsLogger.info(LTag.PUMPCOMM, "Nonce: ${keys.nonce}")
 
-            emitter.onNext(PodEvent.Connected(ltk.podId.toLong())) // TODO supply actual pod id
+            sessionKeys = keys
+            msgIO = mIO
+
+            emitter.onNext(PodEvent.Connected(ltk.podId.toLong()))
 
             emitter.onComplete()
         } catch (ex: Exception) {
diff --git a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/callbacks/BleCommCallbacks.kt b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/callbacks/BleCommCallbacks.kt
index c1d50aa890..72282849bc 100644
--- a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/callbacks/BleCommCallbacks.kt
+++ b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/callbacks/BleCommCallbacks.kt
@@ -30,7 +30,7 @@ class BleCommCallbacks(
 
     override fun onConnectionStateChange(gatt: BluetoothGatt, status: Int, newState: Int) {
         super.onConnectionStateChange(gatt, status, newState)
-        aapsLogger.debug(LTag.PUMPBTCOMM, "OnConnectionStateChange discovered with status/state$status/$newState")
+        aapsLogger.debug(LTag.PUMPBTCOMM, "OnConnectionStateChange with status/state: $status/$newState")
         if (newState == BluetoothProfile.STATE_CONNECTED && status == BluetoothGatt.GATT_SUCCESS) {
             connected.countDown()
         }
diff --git a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/command/BleCommand.kt b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/command/BleCommand.kt
index e437bd23a9..46c19cf6c5 100644
--- a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/command/BleCommand.kt
+++ b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/command/BleCommand.kt
@@ -2,6 +2,15 @@ package info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.command
 
 import info.nightscout.androidaps.utils.extensions.toHex
 
+class BleCommandRTS : BleCommand(BleCommandType.RTS)
+
+class BleCommandCTS : BleCommand(BleCommandType.CTS)
+
+class BleCommandAbort : BleCommand(BleCommandType.ABORT)
+
+class BleCommandSuccess : BleCommand(BleCommandType.SUCCESS)
+
+class BleCommandFail : BleCommand(BleCommandType.FAIL)
 open class BleCommand(val data: ByteArray) {
 
     constructor(type: BleCommandType) : this(byteArrayOf(type.value))
@@ -26,14 +35,4 @@ open class BleCommand(val data: ByteArray) {
     override fun hashCode(): Int {
         return data.contentHashCode()
     }
-}
-
-class BleCommandRTS : BleCommand(BleCommandType.RTS)
-
-class BleCommandCTS : BleCommand(BleCommandType.CTS)
-
-class BleCommandAbort : BleCommand(BleCommandType.ABORT)
-
-class BleCommandSuccess : BleCommand(BleCommandType.SUCCESS)
-
-class BleCommandFail : BleCommand(BleCommandType.FAIL)
+}
\ No newline at end of file
diff --git a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/endecrypt/CryptSequence.kt b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/endecrypt/CryptSequence.kt
index edfc259215..35d638c91c 100644
--- a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/endecrypt/CryptSequence.kt
+++ b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/endecrypt/CryptSequence.kt
@@ -1,24 +1,16 @@
-package info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.session
+package info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.endecrypt
 
 import java.nio.ByteBuffer
 
 class CryptSequence(var sqn: Long) {
 
-    fun incrementForEapAka():ByteArray {
-        sqn++
-        return ByteBuffer.allocate(8)
-            .putLong(sqn)
-            .array()
-            .copyOfRange(2, 8)
-    }
-
-    fun incrementForEnDecrypt(podReceiving: Boolean):ByteArray{
+    fun incrementForEnDecrypt(fromPdmToPod: Boolean): ByteArray {
         sqn++
         val ret = ByteBuffer.allocate(8)
             .putLong(sqn)
             .array()
             .copyOfRange(3, 8)
-        if (podReceiving) {
+        if (fromPdmToPod) {
             ret[0] = (ret[0].toInt() and 127).toByte()
         } else {
             ret[0] = (ret[0].toInt() or 128).toByte()
diff --git a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/endecrypt/EnDecrypt.kt b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/endecrypt/EnDecrypt.kt
index a08b79bf8a..0d359b9952 100644
--- a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/endecrypt/EnDecrypt.kt
+++ b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/endecrypt/EnDecrypt.kt
@@ -18,7 +18,7 @@ class EnDecrypt(private val aapsLogger: AAPSLogger, private val nonce: Nonce, pr
         val payload = msg.payload
         val header = msg.asByteArray().copyOfRange(0, 16)
 
-        val n = nonce.increment()
+        val n = nonce.increment(false)
         aapsLogger.debug(LTag.PUMPBTCOMM, "Decrypt header ${header.toHex()} payload: ${payload.toHex()}")
         aapsLogger.debug(LTag.PUMPBTCOMM, "Decrypt NONCE ${n.toHex()}")
         cipher.init(
@@ -38,7 +38,7 @@ class EnDecrypt(private val aapsLogger: AAPSLogger, private val nonce: Nonce, pr
         val payload = headerMessage.payload
         val header = headerMessage.asByteArray(true).copyOfRange(0, 16)
 
-        val n = nonce.increment()
+        val n = nonce.increment(true)
         aapsLogger.debug(LTag.PUMPBTCOMM, "Encrypt header ${header.toHex()} payload: ${payload.toHex()}")
         aapsLogger.debug(LTag.PUMPBTCOMM, "Encrypt NONCE ${n.toHex()}")
         val encryptedPayload = ByteArray(payload.size + MAC_SIZE)
diff --git a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/endecrypt/Nonce.kt b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/endecrypt/Nonce.kt
new file mode 100644
index 0000000000..a9662820cc
--- /dev/null
+++ b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/endecrypt/Nonce.kt
@@ -0,0 +1,23 @@
+package info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.endecrypt
+
+import java.nio.ByteBuffer
+
+data class Nonce(val prefix: ByteArray, var sqn: Long) {
+    init {
+        require(prefix.size == 8) { "Nonce prefix should be 8 bytes long" }
+    }
+
+    fun increment(podReceiving: Boolean): ByteArray {
+        sqn++
+        val ret = ByteBuffer.allocate(8)
+            .putLong(sqn)
+            .array()
+            .copyOfRange(3, 8)
+        if (podReceiving) {
+            ret[0] = (ret[0].toInt() and 127).toByte()
+        } else {
+            ret[0] = (ret[0].toInt() or 128).toByte()
+        }
+        return prefix + ret
+    }
+}
\ No newline at end of file
diff --git a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/exceptions/FailedToConnectException.kt b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/exceptions/FailedToConnectException.kt
index 4c138d0b2e..07aba43b33 100644
--- a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/exceptions/FailedToConnectException.kt
+++ b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/exceptions/FailedToConnectException.kt
@@ -1,6 +1,5 @@
 package info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.exceptions
 
 open class FailedToConnectException : Exception {
-    constructor() : super()
-    constructor(message: String?) : super(message)
+    constructor(message: String?) : super("Failed to connect: ${message ?: ""}")
 }
diff --git a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/io/BleIO.kt b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/io/BleIO.kt
index f06661da0e..9e6e994aa4 100644
--- a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/io/BleIO.kt
+++ b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/io/BleIO.kt
@@ -123,6 +123,6 @@ class BleIO(
 
     companion object {
 
-        private const val DEFAULT_IO_TIMEOUT_MS = 1000
+        private const val DEFAULT_IO_TIMEOUT_MS = 10000
     }
 }
diff --git a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/message/MessageIO.kt b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/message/MessageIO.kt
index 5c2601311f..5308c88a71 100644
--- a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/message/MessageIO.kt
+++ b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/message/MessageIO.kt
@@ -12,7 +12,7 @@ import info.nightscout.androidaps.utils.extensions.toHex
 
 class MessageIO(private val aapsLogger: AAPSLogger, private val bleIO: BleIO) {
 
-    fun sendMesssage(msg: MessagePacket) {
+    fun sendMessage(msg: MessagePacket) {
         bleIO.flushIncomingQueues()
         bleIO.sendAndConfirmPacket(CharacteristicType.CMD, BleCommandRTS().data)
         val expectCTS = bleIO.receivePacket(CharacteristicType.CMD)
@@ -33,7 +33,6 @@ class MessageIO(private val aapsLogger: AAPSLogger, private val bleIO: BleIO) {
             throw UnexpectedCommandException(BleCommand(expectSuccess))
         }
         // TODO: handle NACKS/FAILS/etc
-        bleIO.flushIncomingQueues()
     }
 
     fun receiveMessage(): MessagePacket {
diff --git a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/message/MessagePacket.kt b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/message/MessagePacket.kt
index eba676f388..e4350db605 100644
--- a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/message/MessagePacket.kt
+++ b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/message/MessagePacket.kt
@@ -24,7 +24,7 @@ data class MessagePacket(
     val version: Short = 0.toShort()
 ) {
 
-    fun asByteArray(): ByteArray {
+    fun asByteArray(forEncryption: Boolean = false): ByteArray {
         val bb = ByteBuffer.allocate(16 + payload.size)
         bb.put(MAGIC_PATTERN.toByteArray())
 
@@ -52,9 +52,10 @@ data class MessagePacket(
         bb.put(f2.value.toByte())
         bb.put(this.sequenceNumber)
         bb.put(this.ackNumber)
-
-        bb.put((this.payload.size ushr 3).toByte())
-        bb.put((this.payload.size shl 5).toByte())
+        val size = payload.size -
+            if (type == MessageType.ENCRYPTED && !forEncryption) 8 else 0
+        bb.put((size ushr 3).toByte())
+        bb.put((size shl 5).toByte())
 
         bb.put(this.source.address)
         bb.put(this.destination.address)
@@ -103,7 +104,7 @@ data class MessagePacket(
                 throw CouldNotParseMessageException(payload)
             }
             val payloadEnd = 16 + size +
-                if (type == MessageType.ENCRYPTED) 8
+                if (type == MessageType.ENCRYPTED) 8 // TAG
                 else 0
 
             return MessagePacket(
diff --git a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/message/PayloadJoiner.kt b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/message/PayloadJoiner.kt
index 2cc75907c1..983a60d374 100644
--- a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/message/PayloadJoiner.kt
+++ b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/message/PayloadJoiner.kt
@@ -29,7 +29,7 @@ class PayloadJoiner(private val firstPacket: ByteArray) {
             firstPacket.size < FirstBlePacket.HEADER_SIZE_WITHOUT_MIDDLE_PACKETS ->
                 throw IncorrectPacketException(0, firstPacket)
 
-            fullFragments == 0 -> {
+            fullFragments == 0                                                   -> {
                 crc = ByteBuffer.wrap(firstPacket.copyOfRange(2, 6)).int.toUnsignedLong()
                 val rest = firstPacket[6]
                 val end = min(rest + FirstBlePacket.HEADER_SIZE_WITHOUT_MIDDLE_PACKETS, BlePacket.MAX_SIZE)
@@ -41,10 +41,10 @@ class PayloadJoiner(private val firstPacket: ByteArray) {
             }
 
             // With middle packets
-            firstPacket.size < BlePacket.MAX_SIZE ->
+            firstPacket.size < BlePacket.MAX_SIZE                                ->
                 throw IncorrectPacketException(0, firstPacket)
 
-            else -> {
+            else                                                                 -> {
                 fragments.add(
                     firstPacket.copyOfRange(
                         FirstBlePacket.HEADER_SIZE_WITH_MIDDLE_PACKETS,
@@ -65,7 +65,7 @@ class PayloadJoiner(private val firstPacket: ByteArray) {
         }
         expectedIndex++
         when {
-            idx < fullFragments -> { // this is a middle fragment
+            idx < fullFragments  -> { // this is a middle fragment
                 if (packet.size < BlePacket.MAX_SIZE) {
                     throw IncorrectPacketException(idx.toByte(), packet)
                 }
@@ -86,7 +86,7 @@ class PayloadJoiner(private val firstPacket: ByteArray) {
                 fragments.add(packet.copyOfRange(LastBlePacket.HEADER_SIZE, packet.size))
             }
 
-            idx > fullFragments -> { // this is the extra fragment
+            idx > fullFragments  -> { // this is the extra fragment
                 val size = packet[1].toInt()
                 if (packet.size < LastOptionalPlusOneBlePacket.HEADER_SIZE + size) {
                     throw IncorrectPacketException(idx.toByte(), packet)
diff --git a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/message/StringLengthPrefixEncoding.kt b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/message/StringLengthPrefixEncoding.kt
index 786a210bfb..efc4d63723 100644
--- a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/message/StringLengthPrefixEncoding.kt
+++ b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/message/StringLengthPrefixEncoding.kt
@@ -18,15 +18,15 @@ class StringLengthPrefixEncoding {
             var remaining = payload
             for ((index, key) in keys.withIndex()) {
                 when {
-                    remaining.size < key.length ->
+                    remaining.size < key.length                                     ->
                         throw MessageIOException("Payload too short: ${payload.toHex()} for key: $key")
                     !(remaining.copyOfRange(0, key.length).decodeToString() == key) ->
                         throw MessageIOException("Key not found: $key in ${payload.toHex()}")
                     // last key can be empty, no length
-                    index == keys.size - 1 && remaining.size == key.length ->
+                    index == keys.size - 1 && remaining.size == key.length          ->
                         return ret
 
-                    remaining.size < key.length + LENGTH_BYTES ->
+                    remaining.size < key.length + LENGTH_BYTES                      ->
                         throw MessageIOException("Length not found: for $key in ${payload.toHex()}")
                 }
                 remaining = remaining.copyOfRange(key.length, remaining.size)
@@ -43,14 +43,17 @@ class StringLengthPrefixEncoding {
         fun formatKeys(keys: Array<String>, payloads: Array<ByteArray>): ByteArray {
             val payloadTotalSize = payloads.fold(0) { acc, i -> acc + i.size }
             val keyTotalSize = keys.fold(0) { acc, i -> acc + i.length }
+            val zeros = payloads.fold(0) { acc, i -> acc + if (i.size == 0) 1 else 0 }
 
-            val bb = ByteBuffer.allocate(2 * keys.size + keyTotalSize + payloadTotalSize)
+            val bb = ByteBuffer.allocate(2 * (keys.size - zeros) + keyTotalSize + payloadTotalSize)
             for (idx in keys.indices) {
                 val k = keys[idx]
                 val payload = payloads[idx]
                 bb.put(k.toByteArray())
-                bb.putShort(payload.size.toShort())
-                bb.put(payload)
+                if (payload.size > 0) {
+                    bb.putShort(payload.size.toShort())
+                    bb.put(payload)
+                }
             }
 
             val ret = ByteArray(bb.position())
diff --git a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/pair/LTKExchanger.kt b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/pair/LTKExchanger.kt
index 4e586ba581..3cab3565a7 100644
--- a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/pair/LTKExchanger.kt
+++ b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/pair/LTKExchanger.kt
@@ -40,11 +40,11 @@ internal class LTKExchanger(private val aapsLogger: AAPSLogger, private val msgI
     fun negotiateLTK(): PairResult {
         // send SP1, SP2
         val sp1sp2 = sp1sp2(nodeId.address, sp2())
-        msgIO.sendMesssage(sp1sp2.messagePacket)
+        msgIO.sendMessage(sp1sp2.messagePacket)
 
         seq++
         val sps1 = sps1()
-        msgIO.sendMesssage(sps1.messagePacket)
+        msgIO.sendMessage(sps1.messagePacket)
         // send SPS1
 
         // read SPS1
@@ -55,7 +55,7 @@ internal class LTKExchanger(private val aapsLogger: AAPSLogger, private val msgI
         seq++
         // send SPS2
         val sps2 = sps2()
-        msgIO.sendMesssage(sps2.messagePacket)
+        msgIO.sendMessage(sps2.messagePacket)
         // read SPS2
 
         val podSps2 = msgIO.receiveMessage()
@@ -63,7 +63,7 @@ internal class LTKExchanger(private val aapsLogger: AAPSLogger, private val msgI
 
         seq++
         // send SP0GP0
-        msgIO.sendMesssage(sp0gp0().messagePacket)
+        msgIO.sendMessage(sp0gp0().messagePacket)
         // read P0
 
         // TODO: failing to read or validate p0 will lead to undefined state
@@ -77,7 +77,7 @@ internal class LTKExchanger(private val aapsLogger: AAPSLogger, private val msgI
         return PairResult(
             ltk = ltk,
             podId = nodeId,
-            seq = seq
+            msgSeq = seq,
         )
     }
 
diff --git a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/pair/PairResult.kt b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/pair/PairResult.kt
index 80aed263ab..c6d087f38d 100644
--- a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/pair/PairResult.kt
+++ b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/pair/PairResult.kt
@@ -3,7 +3,7 @@ package info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.pair
 import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.Id
 import info.nightscout.androidaps.utils.extensions.toHex
 
-data class PairResult(val ltk: ByteArray, val podId: Id, val seq: Byte) {
+data class PairResult(val ltk: ByteArray, val podId: Id, val msgSeq: Byte) {
     init {
         require(ltk.size == 16) { "LTK length must be 16 bytes. Received LTK: ${ltk.toHex()}" }
     }
diff --git a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/session/EapAkaAttribute.kt b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/session/EapAkaAttribute.kt
index ad193b87b8..726d567151 100644
--- a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/session/EapAkaAttribute.kt
+++ b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/session/EapAkaAttribute.kt
@@ -44,7 +44,7 @@ sealed class EapAkaAttribute {
                         ret.add(EapAkaAttributeRes.parse(tail.copyOfRange(2, size)))
                     EapAkaAttributeType.AT_CUSTOM_IV ->
                         ret.add(EapAkaAttributeCustomIV.parse(tail.copyOfRange(2, size)))
-                    else ->
+                    else                             ->
                         throw MessageIOException("Could not parse EAP attributes: ${payload.toHex()}. Expecting only AT_RES or CUSTOM_IV attribute types from the POD")
                 }
                 tail = tail.copyOfRange(size, tail.size)
diff --git a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/session/EapSqn.kt b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/session/EapSqn.kt
index 1861167a50..ef1b4bdc11 100644
--- a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/session/EapSqn.kt
+++ b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/session/EapSqn.kt
@@ -1,4 +1,18 @@
 package info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.session
 
-class EapSqn {
+import java.nio.ByteBuffer
+
+/***
+ * Eap-Aka start session sequence.
+ * Incremented for each new session
+ */
+class EapSqn(var sqn: Long) {
+
+    fun increment(): ByteArray {
+        sqn++
+        return ByteBuffer.allocate(8)
+            .putLong(sqn)
+            .array()
+            .copyOfRange(2, 8)
+    }
 }
\ No newline at end of file
diff --git a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/session/Session.kt b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/session/Session.kt
new file mode 100644
index 0000000000..af4f6d0c27
--- /dev/null
+++ b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/session/Session.kt
@@ -0,0 +1,98 @@
+package info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.session
+
+import info.nightscout.androidaps.logging.AAPSLogger
+import info.nightscout.androidaps.logging.LTag
+import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.Id
+import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.endecrypt.EnDecrypt
+import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.message.MessageIO
+import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.message.MessagePacket
+import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.message.MessageType
+import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.message.StringLengthPrefixEncoding
+import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.message.StringLengthPrefixEncoding.Companion.parseKeys
+import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.pod.command.base.Command
+import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.pod.response.NakResponse
+import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.pod.response.Response
+import info.nightscout.androidaps.utils.extensions.toHex
+
+class Session(
+    private val aapsLogger: AAPSLogger,
+    private val msgIO: MessageIO,
+    private val myId: Id,
+    private val podId: Id,
+    val sessionKeys: SessionKeys,
+    val enDecrypt: EnDecrypt
+) {
+
+    /**
+     * Used for commands:
+     *  -> command with retries
+     *  <- response, ACK TODO: retries?
+     *  -> ACK
+     */
+    fun sendCommand(cmd: Command): Response {
+        sessionKeys.msgSequenceNumber++
+        aapsLogger.debug(LTag.PUMPBTCOMM, "Sending command: ${cmd.encoded.toHex()}")
+
+        val msg = getCmdMessage(cmd)
+        aapsLogger.debug(LTag.PUMPBTCOMM, "Sending command(wrapped): ${msg.payload.toHex()}")
+        msgIO.sendMessage(msg)
+
+        val responseMsg = msgIO.receiveMessage()
+        val decrypted = enDecrypt.decrypt(responseMsg)
+        aapsLogger.debug(LTag.PUMPBTCOMM, "Received response: $decrypted")
+        val response = parseResponse(decrypted)
+
+        sessionKeys.msgSequenceNumber++
+        val ack = getAck(responseMsg)
+        aapsLogger.debug(LTag.PUMPBTCOMM, "Sending ACK: ${ack.payload.toHex()}")
+        msgIO.sendMessage(ack)
+        return response
+    }
+
+    private fun parseResponse(decrypted: MessagePacket): Response {
+        val payload = parseKeys(arrayOf(RESPONSE_PREFIX), decrypted.payload)[0]
+        return NakResponse(payload)
+    }
+
+    private fun getAck(response: MessagePacket): MessagePacket {
+        val msg = MessagePacket(
+            type = MessageType.ENCRYPTED,
+            sequenceNumber = sessionKeys.msgSequenceNumber,
+            source = myId,
+            destination = podId,
+            payload = ByteArray(0),
+            eqos = 1,
+            ack = true,
+            ackNumber = response.sequenceNumber.inc(),
+        )
+        return enDecrypt.encrypt((msg))
+    }
+
+    private fun getCmdMessage(cmd: Command): MessagePacket {
+        val wrapped = StringLengthPrefixEncoding.formatKeys(
+            arrayOf(COMMAND_PREFIX, COMMAND_SUFFIX),
+            arrayOf(cmd.encoded, ByteArray(0))
+        )
+
+        aapsLogger.debug(LTag.PUMPBTCOMM, "Sending command: ${wrapped.toHex()}")
+
+        val msg = MessagePacket(
+            type = MessageType.ENCRYPTED,
+            sequenceNumber = sessionKeys.msgSequenceNumber,
+            source = myId,
+            destination = podId,
+            payload = wrapped,
+            eqos = 1
+        )
+
+        return enDecrypt.encrypt(msg)
+    }
+
+    companion object {
+
+        private const val COMMAND_PREFIX = "S0.0="
+        private const val COMMAND_SUFFIX = ",G0.0"
+        private const val RESPONSE_PREFIX = "0.0="
+
+    }
+}
\ No newline at end of file
diff --git a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/session/SessionEstablisher.kt b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/session/SessionEstablisher.kt
index e4cda0594b..6677742ba8 100644
--- a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/session/SessionEstablisher.kt
+++ b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/session/SessionEstablisher.kt
@@ -4,25 +4,29 @@ import info.nightscout.androidaps.logging.AAPSLogger
 import info.nightscout.androidaps.logging.LTag
 import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.Id
 import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.OmnipodDashBleManagerImpl
+import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.endecrypt.Nonce
 import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.exceptions.SessionEstablishmentException
 import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.message.MessageIO
 import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.message.MessagePacket
 import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.message.MessageType
 import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.pair.PairResult
 import info.nightscout.androidaps.utils.extensions.toHex
-import org.spongycastle.util.encoders.Hex
 import java.security.SecureRandom
 
-class SessionEstablisher(private val aapsLogger: AAPSLogger, private val msgIO: MessageIO, private val ltk: PairResult) {
+class SessionEstablisher(
+    private val aapsLogger: AAPSLogger,
+    private val msgIO: MessageIO,
+    private val ltk: PairResult,
+    private val eapSqn: EapSqn
+) {
 
-    var seq = ltk.seq
+    var sequenceNumber = ltk.msgSeq
 
     private val controllerIV = ByteArray(IV_SIZE)
     private var nodeIV = ByteArray(IV_SIZE)
 
     private val controllerId = Id.fromInt(OmnipodDashBleManagerImpl.CONTROLLER_ID)
-    private val sqn = byteArrayOf(0, 0, 0, 0, 0, 2)
-    private val milenage = Milenage(aapsLogger, ltk.ltk, sqn)
+    private val milenage = Milenage(aapsLogger, ltk.ltk, eapSqn.increment())
 
     init {
         aapsLogger.debug(LTag.PUMPBTCOMM, "Starting EAP-AKA")
@@ -32,21 +36,24 @@ class SessionEstablisher(private val aapsLogger: AAPSLogger, private val msgIO:
 
     fun negotiateSessionKeys(): SessionKeys {
         // send EAP-AKA challenge
-        seq++ //TODO: get from pod state. This only works for activating a new pod
+        sequenceNumber++ //TODO: get from pod state. This only works for activating a new pod
         var challenge = eapAkaChallenge()
-        msgIO.sendMesssage(challenge)
+        msgIO.sendMessage(challenge)
 
         val challengeResponse = msgIO.receiveMessage()
         processChallengeResponse(challengeResponse)  //TODO: what do we have to answer if challenge response does not validate?
 
-        seq++
+        sequenceNumber++
         var success = eapSuccess()
-        msgIO.sendMesssage(success)
+        msgIO.sendMessage(success)
 
         return SessionKeys(
-            ck=milenage.ck,
-            noncePrefix = controllerIV + nodeIV,
-            sqn=sqn
+            ck = milenage.ck,
+            nonce = Nonce(
+                prefix = controllerIV + nodeIV,
+                sqn = 0
+            ),
+            msgSequenceNumber = sequenceNumber
         )
     }
 
@@ -64,7 +71,7 @@ class SessionEstablisher(private val aapsLogger: AAPSLogger, private val msgIO:
         )
         return MessagePacket(
             type = MessageType.SESSION_ESTABLISHMENT,
-            sequenceNumber = seq,
+            sequenceNumber = sequenceNumber,
             source = controllerId,
             destination = ltk.podId,
             payload = eapMsg.toByteArray()
@@ -86,7 +93,7 @@ class SessionEstablisher(private val aapsLogger: AAPSLogger, private val msgIO:
                     }
                 is EapAkaAttributeCustomIV ->
                     nodeIV = attr.payload.copyOfRange(0, IV_SIZE)
-                else ->
+                else                       ->
                     throw SessionEstablishmentException("Unknown attribute received: $attr")
             }
         }
@@ -101,7 +108,7 @@ class SessionEstablisher(private val aapsLogger: AAPSLogger, private val msgIO:
 
         return MessagePacket(
             type = MessageType.SESSION_ESTABLISHMENT,
-            sequenceNumber = seq,
+            sequenceNumber = sequenceNumber,
             source = controllerId,
             destination = ltk.podId,
             payload = eapMsg.toByteArray()
diff --git a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/session/SessionKeys.kt b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/session/SessionKeys.kt
index e321be9c91..e4fb6a04d5 100644
--- a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/session/SessionKeys.kt
+++ b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/comm/session/SessionKeys.kt
@@ -1,9 +1,9 @@
 package info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.session
 
-data class SessionKeys(val ck: ByteArray, val noncePrefix: ByteArray, val sqn: ByteArray) {
+import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.comm.endecrypt.Nonce
+
+data class SessionKeys(val ck: ByteArray, val nonce: Nonce, var msgSequenceNumber: Byte) {
     init {
         require(ck.size == 16) { "CK has to be 16 bytes long" }
-        require(noncePrefix.size == 8) { "noncePrefix has to be 8 bytes long" }
-        require(sqn.size == 6) { "SQN has to be 6 bytes long" }
     }
 }
diff --git a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/event/PodEvent.kt b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/event/PodEvent.kt
index b0429dd1d5..75775945c7 100644
--- a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/event/PodEvent.kt
+++ b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/driver/event/PodEvent.kt
@@ -18,5 +18,5 @@ sealed class PodEvent {
     /* Message exchange events */
     class CommandSending(val command: Command) : PodEvent()
     class CommandSent(val command: Command) : PodEvent()
-    class ResponseReceived(val response: Response) : PodEvent()
+    class ResponseReceived(val response:Response) : PodEvent()
 }
diff --git a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/ui/OmnipodDashOverviewFragment.kt b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/ui/OmnipodDashOverviewFragment.kt
index 66fbfbf27a..275e995c91 100644
--- a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/ui/OmnipodDashOverviewFragment.kt
+++ b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/ui/OmnipodDashOverviewFragment.kt
@@ -324,13 +324,8 @@ class OmnipodDashOverviewFragment : DaggerFragment() {
                 )
             }
 
-            podInfoBinding.podActiveAlerts.text = if (podStateManager.activeAlerts!!.size > 0) {
-                // TODO
-                // TextUtils.join(System.lineSeparator(), omnipodUtil.getTranslatedActiveAlerts(podStateManager))
-                "TODO"
-            } else {
-                PLACEHOLDER
-            }
+            podInfoBinding.podActiveAlerts.text = PLACEHOLDER
+
         }
 
         if (errors.size == 0) {
diff --git a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/ui/wizard/deactivation/viewmodel/action/DashDeactivatePodViewModel.kt b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/ui/wizard/deactivation/viewmodel/action/DashDeactivatePodViewModel.kt
index 9d2ad3a869..8a6ec92571 100644
--- a/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/ui/wizard/deactivation/viewmodel/action/DashDeactivatePodViewModel.kt
+++ b/omnipod-dash/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/dash/ui/wizard/deactivation/viewmodel/action/DashDeactivatePodViewModel.kt
@@ -6,16 +6,18 @@ import info.nightscout.androidaps.data.PumpEnactResult
 import info.nightscout.androidaps.logging.AAPSLogger
 import info.nightscout.androidaps.plugins.pump.omnipod.common.R
 import info.nightscout.androidaps.plugins.pump.omnipod.common.ui.wizard.deactivation.viewmodel.action.DeactivatePodViewModel
+import info.nightscout.androidaps.plugins.pump.omnipod.dash.driver.OmnipodDashManager
 import io.reactivex.Single
 import javax.inject.Inject
 
 class DashDeactivatePodViewModel @Inject constructor(
+    private val omnipodManager: OmnipodDashManager,
     injector: HasAndroidInjector,
     logger: AAPSLogger
 ) : DeactivatePodViewModel(injector, logger) {
 
     override fun doExecuteAction(): Single<PumpEnactResult> = Single.just(
-        PumpEnactResult(injector).success(false).comment("TODO")
+     PumpEnactResult(injector).success(true).comment("TODO")
     ) // TODO
 
     override fun discardPod() {