diff --git a/src/lib/core/WeaveConfig.h b/src/lib/core/WeaveConfig.h
index 270bc51..b3990a2 100644
--- a/src/lib/core/WeaveConfig.h
+++ b/src/lib/core/WeaveConfig.h
@@ -1881,6 +1881,22 @@
 #define WEAVE_CONFIG_ENABLE_CONDITION_LOGGING 0
 #endif // WEAVE_CONFIG_ENABLE_CONDITION_LOGGING
 
+/**
+ *  @def WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+ *
+ *  @brief
+ *    If set to (1), use of the persistent subscription state
+ *    implementation is enabled. Default value is (0) or disabled.
+ *
+ *  @note
+ *    Enabling this profile allows applications using Weave to
+ *    persist the mutual subscription states between device and service
+ *    across device reboots.
+ *
+ */
+#ifndef WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+#define WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE               0
+#endif // WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
 
 /**
  *  @def WEAVE_CONFIG_ENABLE_SERVICE_DIRECTORY
@@ -2356,6 +2372,25 @@
 #endif // WEAVE_CONFIG_MAX_SOFTWARE_VERSION_LENGTH
 
 /**
+ *  @def WEAVE_CONFIG_ENABLE_OFFLOAD_EVENTS_FIRST
+ *
+ *  @brief
+ *    Enable offloading of events before trait properties
+ *
+ *  When this option is enabled, WeaveDataManagement will first
+ *  attempt to pack events from the eventlist into the NotifyRequest
+ *  message before adding modified trait data properties from
+ *  the datalist.
+ *
+ *  This feature can be useful in systems that might need
+ *  the events to be dispatched as early as possible.
+ *
+ */
+#ifndef WEAVE_CONFIG_ENABLE_OFFLOAD_EVENTS_FIRST
+#define WEAVE_CONFIG_ENABLE_OFFLOAD_EVENTS_FIRST            0
+#endif // WEAVE_CONFIG_ENABLE_OFFLOAD_EVENTS_FIRST
+
+/**
  * @def WEAVE_NON_PRODUCTION_MARKER
  *
  * @brief Defines the name of a mark symbol whose presence signals that the Weave code
diff --git a/src/lib/profiles/data-management/Current/NotificationEngine.cpp b/src/lib/profiles/data-management/Current/NotificationEngine.cpp
index 509e692..f26df90 100644
--- a/src/lib/profiles/data-management/Current/NotificationEngine.cpp
+++ b/src/lib/profiles/data-management/Current/NotificationEngine.cpp
@@ -1152,6 +1152,9 @@
             size_t i                  = static_cast<size_t>(iterator - kImportanceType_First);
             ImportanceType importance = (ImportanceType) iterator;
             logger.NotifyEventsDelivered(importance, aSubHandler->mSelfVendedEvents[i] - 1, aSubHandler->GetPeerNodeId());
+#if WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+            aSubHandler->UpdateDeliveredEvents(importance);
+#endif // WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
         }
     }
 
@@ -1421,6 +1424,18 @@
 
             // Ensure we're in the DataList element.  May allocate memory.
             err = aNotifyRequest.MoveToState(kNotifyRequestBuilder_BuildDataList);
+
+#if WEAVE_CONFIG_ENABLE_OFFLOAD_EVENTS_FIRST
+            // if we did not have enough space for data list at all,
+            // squash the error and exit immediately. This check is necessary here
+            // when we are loading from the datalist after having loaded the event
+            // list into the buffer already.
+            if ((err == WEAVE_ERROR_NO_MEMORY) || (err == WEAVE_ERROR_BUFFER_TOO_SMALL))
+            {
+                err = WEAVE_NO_ERROR;
+                ExitNow();
+            }
+#endif // WEAVE_CONFIG_ENABLE_OFFLOAD_EVENTS_FIRST
             SuccessOrExit(err);
 
             // Make a back-up of the writer so that we can rewind back if the next retrieval fails due to the packet getting full.
@@ -1550,6 +1565,20 @@
     // Fill in the DataList.  Allocation may take place
     subClean = true;
 
+#if WEAVE_CONFIG_ENABLE_OFFLOAD_EVENTS_FIRST
+
+#if WEAVE_CONFIG_EVENT_LOGGING_WDM_OFFLOAD
+    // Fill in the EventList.  Allocation may take place
+    err = BuildSingleNotifyRequestEventList(aSubHandler, notifyRequest, subClean, neWriteInProgress);
+    SuccessOrExit(err);
+#endif
+
+    aIsSubscriptionClean &= subClean;
+    subClean = true;
+
+    err = BuildSingleNotifyRequestDataList(aSubHandler, notifyRequest, subClean, neWriteInProgress);
+    SuccessOrExit(err);
+#else
     err = BuildSingleNotifyRequestDataList(aSubHandler, notifyRequest, subClean, neWriteInProgress);
     SuccessOrExit(err);
 
@@ -1561,6 +1590,7 @@
     err = BuildSingleNotifyRequestEventList(aSubHandler, notifyRequest, subClean, neWriteInProgress);
     SuccessOrExit(err);
 #endif
+#endif // WEAVE_CONFIG_ENABLE_OFFLOAD_EVENTS_FIRST
 
     aIsSubscriptionClean &= subClean;
 
diff --git a/src/lib/profiles/data-management/Current/SubscriptionClient.cpp b/src/lib/profiles/data-management/Current/SubscriptionClient.cpp
index 3603532..a4319f1 100644
--- a/src/lib/profiles/data-management/Current/SubscriptionClient.cpp
+++ b/src/lib/profiles/data-management/Current/SubscriptionClient.cpp
@@ -165,6 +165,153 @@
     return err;
 }
 
+#if WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+// load subscription id and liveness timeout
+// AddRef to Binding
+// store pointers to binding and delegate
+// move to kState_SubscriptionEstablished_Idle
+WEAVE_ERROR SubscriptionClient::LoadFromPersistedState(Binding * const apBinding, void * const apAppState, EventCallback const aEventCallback,
+                                                       const TraitCatalogBase<TraitDataSink> * const apCatalog,
+                                                       const uint32_t aInactivityTimeoutDuringSubscribingMsec, IWeaveWDMMutex * aUpdateMutex,
+                                                       TLVReader & reader)
+{
+    WEAVE_ERROR err = WEAVE_NO_ERROR;
+    WeaveLogIfFalse(0 == mRefCount);
+
+    // AddRef for the duration of this method
+    _AddRef();
+
+    // add reference to the binding
+    apBinding->AddRef();
+
+    // set subscription id and liveness timeout
+    err = LoadSubscriptionState(reader);
+    SuccessOrExit(err);
+
+    // make a copy of the pointers
+    mBinding                                = apBinding;
+    mAppState                               = apAppState;
+    mEventCallback                          = aEventCallback;
+
+    // Set the protocol callback on the binding object so that the SubscriptionClient gets
+    // notified of changes in the binding's state.
+    mBinding->SetProtocolLayerCallback(BindingEventCallback, this);
+
+    err = _PrepareBinding();
+    SuccessOrExit(err);
+
+    if (NULL == apCatalog)
+    {
+        mDataSinkCatalog = NULL;
+    }
+    else
+    {
+        mDataSinkCatalog = const_cast <TraitCatalogBase<TraitDataSink>*>(apCatalog);
+    }
+
+    mInactivityTimeoutDuringSubscribingMsec = aInactivityTimeoutDuringSubscribingMsec;
+
+
+#if WEAVE_CONFIG_ENABLE_WDM_UPDATE
+    mUpdateMutex                            = aUpdateMutex;
+    mUpdateInFlight                         = false;
+    mMaxUpdateSize                          = 0;
+
+    err = mUpdateClient.Init(mBinding, this, UpdateEventCallback);
+    SuccessOrExit(err);
+
+    ConfigureUpdatableSinks();
+
+#endif // WEAVE_CONFIG_ENABLE_WDM_UPDATE
+
+    // Hold this instance until we clear the protocol state machine
+    _AddRef();
+    MoveToState(kState_SubscriptionEstablished_Idle);
+
+    WeaveLogDetail(DataManagement, "Client[%u] [%5.5s] %s Ref(%d)", SubscriptionEngine::GetInstance()->GetClientId(this),
+                   GetStateStr(), __func__, mRefCount);
+
+    {
+        InEventParam inParam;
+        OutEventParam outParam;
+
+        // Emit an OnSubscriptionActivity event to the application.
+        inParam.mSubscriptionActivity.mClient = this;
+        mEventCallback(mAppState, kEvent_OnSubscriptionActivity, inParam, outParam);
+
+        // Emit an OnSubscriptionEstablished event to the application.
+        // Note that it's allowed to cancel or even abandon this subscription right inside this callback.
+        inParam.mSubscriptionEstablished.mSubscriptionId = mSubscriptionId;
+        inParam.mSubscriptionEstablished.mClient         = this;
+        mEventCallback(mAppState, kEvent_OnSubscriptionEstablished, inParam, outParam);
+    }
+
+exit:
+    _Release();
+    return err;
+}
+
+WEAVE_ERROR SubscriptionClient::SerializeSubscriptionState(TLVWriter & writer)
+{
+    WEAVE_ERROR err = WEAVE_NO_ERROR;
+
+    TLV::TLVType container;
+
+    err = writer.StartContainer(TLV::AnonymousTag, TLV::kTLVType_Structure, container);
+    SuccessOrExit(err);
+
+    err = writer.Put(TLV::ContextTag(kTag_PersistSubscriptionClient_SubscriptionId), mSubscriptionId);
+    SuccessOrExit(err);
+    err = writer.Put(TLV::ContextTag(kTag_PersistSubscriptionClient_LivenessTimeoutMsec), mLivenessTimeoutMsec);
+    SuccessOrExit(err);
+
+    err = writer.EndContainer(container);
+    SuccessOrExit(err);
+
+exit:
+
+    if (err != WEAVE_NO_ERROR)
+    {
+        WeaveLogError(DataManagement, "Serialize persistent subscription data for subscription client error: %d", err);
+    }
+    return err;
+}
+
+WEAVE_ERROR SubscriptionClient::LoadSubscriptionState(TLVReader & reader)
+{
+    WEAVE_ERROR err = WEAVE_NO_ERROR;
+
+    TLV::TLVType container;
+
+    err = reader.Next(TLV::kTLVType_Structure, TLV::AnonymousTag);
+    SuccessOrExit(err);
+    err = reader.EnterContainer(container);
+    SuccessOrExit(err);
+
+    err = reader.Next(TLV::kTLVType_UnsignedInteger, TLV::ContextTag(kTag_PersistSubscriptionClient_SubscriptionId));
+    SuccessOrExit(err);
+    err = reader.Get(mSubscriptionId);
+    SuccessOrExit(err);
+
+    err = reader.Next(TLV::kTLVType_UnsignedInteger, TLV::ContextTag(kTag_PersistSubscriptionClient_LivenessTimeoutMsec));
+    SuccessOrExit(err);
+    err = reader.Get(mLivenessTimeoutMsec);
+    SuccessOrExit(err);
+
+    err = reader.ExitContainer(container);
+    SuccessOrExit(err);
+
+
+exit:
+
+    if (err != WEAVE_NO_ERROR)
+    {
+        WeaveLogError(DataManagement, "Load persistent subscription data for subscription client error: %d", err);
+    }
+    return err;
+}
+#endif // WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+
 #if WEAVE_DETAIL_LOGGING
 const char * SubscriptionClient::GetStateStr() const
 {
diff --git a/src/lib/profiles/data-management/Current/SubscriptionClient.h b/src/lib/profiles/data-management/Current/SubscriptionClient.h
index 5e3fb05..0ab3825 100644
--- a/src/lib/profiles/data-management/Current/SubscriptionClient.h
+++ b/src/lib/profiles/data-management/Current/SubscriptionClient.h
@@ -450,6 +450,18 @@
         kConfig_CounterSubscriber /**< Start a "counter subscription" */
     };
 
+#if WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+    /**
+     * @brief
+     *  Tags for the persistent subscription data
+     */
+    enum
+    {
+        kTag_PersistSubscriptionClient_SubscriptionId          = 1,
+        kTag_PersistSubscriptionClient_LivenessTimeoutMsec     = 2
+    };
+#endif // WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+
     bool IsInitiator() { return mConfig == kConfig_Initiator; }
     bool IsCounterSubscriber() { return mConfig == kConfig_CounterSubscriber; }
     bool ShouldSubscribe() { return mConfig > kConfig_Down; }
@@ -495,6 +507,20 @@
                      const TraitCatalogBase<TraitDataSink> * const apCatalog,
                      const uint32_t aInactivityTimeoutDuringSubscribingMsec, IWeaveWDMMutex * aUpdateMutex);
 
+#if WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+    // load subscription id and liveness timeout
+    // AddRef to Binding
+    // store pointers to binding and delegate
+    // move to kState_SubscriptionEstablished_Idle
+    WEAVE_ERROR LoadFromPersistedState(Binding * const apBinding, void * const apAppState, EventCallback const aEventCallback,
+                                       const TraitCatalogBase<TraitDataSink> * const apCatalog,
+                                       const uint32_t aInactivityTimeoutDuringSubscribingMsec, IWeaveWDMMutex * aUpdateMutex,
+                                       TLVReader & reader);
+
+    WEAVE_ERROR SerializeSubscriptionState(TLVWriter & writer);
+    WEAVE_ERROR LoadSubscriptionState(TLVReader & reader);
+#endif // WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+
     void _InitiateSubscription(void);
     WEAVE_ERROR SendSubscribeRequest(void);
 
diff --git a/src/lib/profiles/data-management/Current/SubscriptionEngine.cpp b/src/lib/profiles/data-management/Current/SubscriptionEngine.cpp
index b37a1c5..8070e27 100644
--- a/src/lib/profiles/data-management/Current/SubscriptionEngine.cpp
+++ b/src/lib/profiles/data-management/Current/SubscriptionEngine.cpp
@@ -283,6 +283,104 @@
     return NewClient(appClient, apBinding, apAppState, aEventCallback, apCatalog, aInactivityTimeoutDuringSubscribingMsec, NULL);
 }
 
+#if WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+WEAVE_ERROR SubscriptionEngine::NewClientFromPersistedState(SubscriptionClient ** const appClient, Binding * const apBinding, void * const apAppState,
+                                                            SubscriptionClient::EventCallback const aEventCallback,
+                                                            const TraitCatalogBase<TraitDataSink> * const apCatalog,
+                                                            const uint32_t aInactivityTimeoutDuringSubscribingMsec, TLVReader & reader)
+{
+    WEAVE_ERROR err = WEAVE_ERROR_NO_MEMORY;
+
+#if WEAVE_CONFIG_ENABLE_WDM_UPDATE
+    uint32_t maxSize = WDM_MAX_UPDATE_SIZE;
+#endif // WEAVE_CONFIG_ENABLE_WDM_UPDATE
+
+    WEAVE_FAULT_INJECT(FaultInjection::kFault_WDM_SubscriptionClientNew, ExitNow());
+
+    *appClient = NULL;
+
+    for (size_t i = 0; i < kMaxNumSubscriptionClients; ++i)
+    {
+        if (SubscriptionClient::kState_Free == mClients[i].mCurrentState)
+        {
+            *appClient = &mClients[i];
+            err =
+                (*appClient)
+                    ->LoadFromPersistedState(apBinding, apAppState, aEventCallback, apCatalog, aInactivityTimeoutDuringSubscribingMsec, NULL, reader);
+
+            if (WEAVE_NO_ERROR != err)
+            {
+                *appClient = NULL;
+                ExitNow();
+            }
+#if WEAVE_CONFIG_ENABLE_WDM_UPDATE
+            mClients[i].SetMaxUpdateSize(maxSize);
+#endif // WEAVE_CONFIG_ENABLE_WDM_UPDATE
+            SYSTEM_STATS_INCREMENT(nl::Weave::System::Stats::kWDM_NumSubscriptionClients);
+            break;
+        }
+    }
+
+exit:
+    if (WEAVE_NO_ERROR != err)
+    {
+        WeaveLogError(DataManagement, "Load persistent subscription client failed with error: %d", err);
+    }
+    return err;
+}
+
+WEAVE_ERROR SubscriptionEngine::NewSubscriptionHandlerFromPersistedState(Binding * const apBinding, void * const apAppState,
+                                                                         SubscriptionHandler::EventCallback const aEventCallback, TLVReader & reader)
+{
+    WEAVE_ERROR err                    = WEAVE_NO_ERROR;
+    SubscriptionHandler * handler      = NULL;
+
+    err = NewSubscriptionHandler(&handler);
+    SuccessOrExit(err);
+
+    handler->SetMaxNotificationSize(WDM_MAX_NOTIFICATION_SIZE);
+    err = handler->LoadFromPersistedState(apBinding, apAppState, aEventCallback, reader);
+    SuccessOrExit(err);
+
+exit:
+    WeaveLogFunctError(err);
+
+    return err;
+}
+
+WEAVE_ERROR SubscriptionEngine::SaveClient(uint64_t aPeerNodeID, TLVWriter &aWriter)
+{
+    WEAVE_ERROR err                      = WEAVE_NO_ERROR;
+    SubscriptionClient * client          = NULL;
+
+    client = FindEstablishedIdleClient(aPeerNodeID);
+    VerifyOrExit(client != NULL, err = WEAVE_ERROR_INCORRECT_STATE);
+
+    err = client->SerializeSubscriptionState(aWriter);
+    SuccessOrExit(err);
+
+exit:
+
+    return err;
+}
+
+WEAVE_ERROR SubscriptionEngine::SaveSubscriptionHandler(uint64_t aPeerNodeID, TLVWriter &aWriter)
+{
+    WEAVE_ERROR err                      = WEAVE_NO_ERROR;
+    SubscriptionHandler * handler        = NULL;
+
+    handler = FindEstablishedIdleHandler(aPeerNodeID);
+    VerifyOrExit(handler != NULL, err = WEAVE_ERROR_INCORRECT_STATE);
+
+    err = handler->SerializeSubscriptionState(aWriter);
+    SuccessOrExit(err);
+
+exit:
+
+    return err;
+}
+#endif // WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+
 /**
  * Reply to a request with a StatuReport message.
  *
@@ -800,6 +898,27 @@
     return result;
 }
 
+#if WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+SubscriptionClient * SubscriptionEngine::FindEstablishedIdleClient(const uint64_t aPeerNodeId)
+{
+    SubscriptionClient * result = NULL;
+
+    for (size_t i = 0; i < kMaxNumSubscriptionClients; ++i)
+    {
+        if (mClients[i].mCurrentState == SubscriptionClient::kState_SubscriptionEstablished_Idle)
+        {
+            if (aPeerNodeId == mClients[i].mBinding->GetPeerNodeId())
+            {
+                result = &mClients[i];
+                break;
+            }
+        }
+    }
+
+    return result;
+}
+#endif // WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+
 bool SubscriptionEngine::UpdateClientLiveness(const uint64_t aPeerNodeId, const uint64_t aSubscriptionId, const bool aKill)
 {
     WEAVE_ERROR err              = WEAVE_NO_ERROR;
@@ -919,6 +1038,27 @@
     return result;
 }
 
+#if WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+SubscriptionHandler * SubscriptionEngine::FindEstablishedIdleHandler(const uint64_t aPeerNodeId)
+{
+    SubscriptionHandler * result = NULL;
+
+    for (size_t i = 0; i < kMaxNumSubscriptionHandlers; ++i)
+    {
+        if (mHandlers[i].mCurrentState == SubscriptionHandler::kState_SubscriptionEstablished_Idle)
+        {
+            if (aPeerNodeId == mHandlers[i].GetPeerNodeId())
+            {
+                result = &mHandlers[i];
+                break;
+            }
+        }
+    }
+
+    return result;
+}
+#endif // WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+
 WEAVE_ERROR SubscriptionEngine::GetMinEventLogPosition(size_t & outLogPosition) const
 {
     WEAVE_ERROR err = WEAVE_NO_ERROR;
diff --git a/src/lib/profiles/data-management/Current/SubscriptionEngine.h b/src/lib/profiles/data-management/Current/SubscriptionEngine.h
index 7ae183d..1dea155 100644
--- a/src/lib/profiles/data-management/Current/SubscriptionEngine.h
+++ b/src/lib/profiles/data-management/Current/SubscriptionEngine.h
@@ -300,8 +300,34 @@
                           const TraitCatalogBase<TraitDataSink> * const apCatalog,
                           const uint32_t aInactivityTimeoutDuringSubscribingMsec, IWeaveWDMMutex * aUpdateMutex);
 
+#if WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+    /**
+     * @brief This is the default event handler to be called by application layer for any ignored or unrecognized event
+     *
+     * @param[in]  appClient        A pointer to pointer for the new subscription client object
+     * @param[in]  apBinding        A pointer to Binding to be used for this subscription client
+     * @param[in]  apAppState       A pointer to application layer supplied state object
+     * @param[in]  aEventCallback   A function pointer for event call back
+     * @param[in]  apCatalog        A pointer to data sink catalog object
+     * @param[in]  aTimeoutMsecBeforeSubscribeResponse    Max number of milliseconds before subscribe
+     *                                                    response must be received after subscribe request is sent
+     * @param[in]  reader           A reference to TLVReader to load subscription client
+     */
+    WEAVE_ERROR NewClientFromPersistedState(SubscriptionClient ** const appClient, Binding * const apBinding, void * const apAppState,
+                                            SubscriptionClient::EventCallback const aEventCallback,
+                                            const TraitCatalogBase<TraitDataSink> * const apCatalog,
+                                            const uint32_t aInactivityTimeoutDuringSubscribingMsec, TLVReader & reader);
+    WEAVE_ERROR SaveClient(uint64_t aPeerNodeID, TLVWriter &aWriter);
+#endif // WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+
     WEAVE_ERROR NewSubscriptionHandler(SubscriptionHandler ** const subHandler);
 
+#if WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+    WEAVE_ERROR NewSubscriptionHandlerFromPersistedState(Binding * const apBinding, void * const apAppState,
+                                                         SubscriptionHandler::EventCallback const aEventCallback, TLVReader & reader);
+    WEAVE_ERROR SaveSubscriptionHandler(uint64_t aPeerNodeID, TLVWriter &aWriter);
+#endif // WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+
     uint16_t GetClientId(const SubscriptionClient * const apClient) const;
 
     SubscriptionClient * FindClient(const uint64_t aPeerNodeId, const uint64_t aSubscriptionId);
@@ -537,6 +563,11 @@
 #endif // WDM_PUBLISHER_ENABLE_CUSTOM_COMMAND_HANDLER
 
 #endif // WDM_ENABLE_SUBSCRIPTION_PUBLISHER
+
+#if WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+    SubscriptionClient * FindEstablishedIdleClient(const uint64_t aPeerNodeId);
+    SubscriptionHandler * FindEstablishedIdleHandler(const uint64_t aPeerNodeId);
+#endif // WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
 };
 
 }; // namespace WeaveMakeManagedNamespaceIdentifier(DataManagement, kWeaveManagedNamespaceDesignation_Current)
diff --git a/src/lib/profiles/data-management/Current/SubscriptionHandler.cpp b/src/lib/profiles/data-management/Current/SubscriptionHandler.cpp
index 12edb52..273f372 100644
--- a/src/lib/profiles/data-management/Current/SubscriptionHandler.cpp
+++ b/src/lib/profiles/data-management/Current/SubscriptionHandler.cpp
@@ -75,6 +75,9 @@
 
     memset(mSelfVendedEvents, 0, sizeof(mSelfVendedEvents));
     memset(mLastScheduledEventId, 0, sizeof(mLastScheduledEventId));
+#if WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+    memset(mDeliveredEvents, 0, sizeof(mDeliveredEvents));
+#endif // WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
 }
 
 WEAVE_ERROR SubscriptionHandler::AcceptSubscribeRequest(const uint32_t aLivenessTimeoutSec)
@@ -510,8 +513,10 @@
                     // mSelfVendedEvents should point to the next event ID that
                     // we publish. Otherwise, we would publish an event that
                     // the subscriber already received.
-                    mSelfVendedEvents[static_cast<uint32_t>(importance) - static_cast<uint32_t>(kImportanceType_First)] =
-                        static_cast<event_id_t>(eventId + 1);
+                    uint32_t i = static_cast<uint32_t>(importance) - static_cast<uint32_t>(kImportanceType_First);
+                    WeaveLogProgress(DataManagement, "Update mSelfVendedEvents[%d] from %d to %d using service data",
+                                     i, mSelfVendedEvents[i], eventId + 1);
+                    mSelfVendedEvents[i] = static_cast<event_id_t>(eventId + 1);
                 }
                 else
                 {
@@ -635,6 +640,14 @@
     return err;
 }
 
+#if WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+void SubscriptionHandler::UpdateDeliveredEvents(ImportanceType importance)
+{
+  uint32_t i = static_cast<uint32_t>(importance) - static_cast<uint32_t>(kImportanceType_First);
+  mDeliveredEvents[i] = mSelfVendedEvents[i] - 1;
+}
+#endif // WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+
 void SubscriptionHandler::InitWithIncomingRequest(Binding * const aBinding, const uint64_t aRandomNumber,
                                                   nl::Weave::ExchangeContext * aEC, const nl::Inet::IPPacketInfo * aPktInfo,
                                                   const nl::Weave::WeaveMessageInfo * aMsgInfo, PacketBuffer * aPayload)
@@ -1753,6 +1766,402 @@
         mMaxNotificationSize = aMaxSize;
 }
 
+#if WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+WEAVE_ERROR SubscriptionHandler::LoadFromPersistedState(Binding * const apBinding, void * const apAppState, EventCallback const aEventCallback, TLVReader & reader)
+{
+    WEAVE_ERROR err                 = WEAVE_NO_ERROR;
+
+    WeaveLogDetail(DataManagement, "Handler[%u] [%5.5s] %s Ref(%d)", SubscriptionEngine::GetInstance()->GetHandlerId(this),
+                   GetStateStr(), __func__, mRefCount);
+
+    WeaveLogIfFalse(0 == mRefCount);
+
+    // AddRef for the duration of this method
+    _AddRef();
+
+    mBinding                                = apBinding;
+    mAppState                               = apAppState;
+    mEventCallback                          = aEventCallback;
+
+    // Capture the binding and arrange to receive event callbacks.
+    mBinding->AddRef();
+    mBinding->SetProtocolLayerCallback(BindingEventCallback, this);
+
+    mBytesOffloaded = 0;
+
+    err = LoadSubscriptionState(reader);
+    SuccessOrExit(err);
+
+    // Hold this instance until we clear the protocol state machine
+    _AddRef();
+    MoveToState(kState_SubscriptionEstablished_Idle);
+
+    {
+        InEventParam inParam;
+        OutEventParam outParam;
+        inParam.mSubscriptionEstablished.mSubscriptionId = mSubscriptionId;
+        inParam.mSubscriptionEstablished.mHandler        = this;
+
+        // Note we could be aborted in this callback
+        mEventCallback(mAppState, kEvent_OnSubscriptionEstablished, inParam, outParam);
+    }
+
+    err = ReplaceExchangeContext();
+    SuccessOrExit(err);
+
+    SubscriptionEngine::GetInstance()->GetNotificationEngine()->Run();
+
+exit:
+    WeaveLogFunctError(err);
+
+    // Run termination if subscription is marked established
+    if (WEAVE_NO_ERROR != err && mCurrentState == kState_SubscriptionEstablished_Idle)
+    {
+        TerminateSubscription(err, NULL, false);
+    }
+
+    _Release();
+
+    return err;
+}
+
+WEAVE_ERROR SubscriptionHandler::LoadSubscriptionState(TLVReader & reader)
+{
+    WEAVE_ERROR err = WEAVE_NO_ERROR;
+
+    TLV::TLVType container;
+
+    err = reader.Next(TLV::kTLVType_Structure, TLV::AnonymousTag);
+    SuccessOrExit(err);
+    err = reader.EnterContainer(container);
+    SuccessOrExit(err);
+
+    err = reader.Next(TLV::kTLVType_UnsignedInteger, TLV::ContextTag(kTag_PersistSubscriptionHandler_PeerNodeId));
+    SuccessOrExit(err);
+    err = reader.Get(mPeerNodeId);
+    SuccessOrExit(err);
+
+    err = reader.Next(TLV::kTLVType_UnsignedInteger, TLV::ContextTag(kTag_PersistSubscriptionHandler_SubscriptionId));
+    SuccessOrExit(err);
+    err = reader.Get(mSubscriptionId);
+    SuccessOrExit(err);
+
+    err = reader.Next(TLV::kTLVType_UnsignedInteger, TLV::ContextTag(kTag_PersistSubscriptionHandler_LivenessTimeoutMsec));
+    SuccessOrExit(err);
+    err = reader.Get(mLivenessTimeoutMsec);
+    SuccessOrExit(err);
+
+    err = reader.Next(TLV::kTLVType_Boolean, TLV::ContextTag(kTag_PersistSubscriptionHandler_IsInitiator));
+    SuccessOrExit(err);
+    err = reader.Get(mIsInitiator);
+    SuccessOrExit(err);
+
+    err = reader.Next(TLV::kTLVType_Boolean, TLV::ContextTag(kTag_PersistSubscriptionHandler_SubscribeToAllEvents));
+    SuccessOrExit(err);
+    err = reader.Get(mSubscribeToAllEvents);
+    SuccessOrExit(err);
+
+    err = LoadTraitInstances(reader);
+    SuccessOrExit(err);
+
+    err = LoadDeliveredEvents(reader);
+    SuccessOrExit(err);
+
+    err = reader.ExitContainer(container);
+    SuccessOrExit(err);
+
+    // Load SelfVendedEvents from DeliveredEvents
+    for (int importance = kImportanceType_First; importance <= kImportanceType_Last; importance++)
+    {
+        uint32_t i = static_cast<uint32_t>(importance) - static_cast<uint32_t>(kImportanceType_First);
+        WeaveLogProgress(DataManagement, "Update mSelfVendedEvents[%d] from %d to %d using persisted data",
+                         i, mSelfVendedEvents[i], 1 + mDeliveredEvents[i]);
+        mSelfVendedEvents[i] = 1 + mDeliveredEvents[i];
+    }
+
+exit:
+
+    if (err != WEAVE_NO_ERROR)
+    {
+        WeaveLogError(DataManagement, "Load persistent subscription data for subscription handler error: %d", err);
+    }
+    return err;
+}
+
+
+WEAVE_ERROR SubscriptionHandler::LoadTraitInstances(TLVReader & reader)
+{
+    WEAVE_ERROR err = WEAVE_NO_ERROR;
+
+    Platform::CriticalSectionEnter();
+
+    TLV::TLVType traitInstanceArrayContainer;
+
+    err = reader.Next(TLV::kTLVType_Array, TLV::ContextTag(kTag_PersistTraitInstances));
+    SuccessOrExit(err);
+    err = reader.EnterContainer(traitInstanceArrayContainer);
+    SuccessOrExit(err);
+
+    while ((err = reader.Next(TLV::kTLVType_Structure, TLV::AnonymousTag)) == WEAVE_NO_ERROR)
+    {
+        TLV::TLVType traitInstanceContainer;
+        TraitDataSource * dataSource;
+        TraitInstanceInfo * traitInstance = NULL;
+        TraitDataHandle traitDataHandle;
+        uint16_t requestedVersion;
+        bool isDirty;
+
+        err = reader.EnterContainer(traitInstanceContainer);
+        SuccessOrExit(err);
+
+        err = reader.Next(TLV::kTLVType_UnsignedInteger, TLV::ContextTag(kTag_PersistTraitInstances_TraitDataHandle));
+        SuccessOrExit(err);
+        err = reader.Get(traitDataHandle);
+        SuccessOrExit(err);
+
+        err = reader.Next(TLV::kTLVType_UnsignedInteger, TLV::ContextTag(kTag_PersistTraitInstances_RequestedVersion));
+        SuccessOrExit(err);
+        err = reader.Get(requestedVersion);
+        SuccessOrExit(err);
+
+        err = reader.Next(TLV::kTLVType_Boolean, TLV::ContextTag(kTag_PersistTraitInstances_IsDirty));
+        SuccessOrExit(err);
+        err = reader.Get(isDirty);
+        SuccessOrExit(err);
+
+        err = reader.ExitContainer(traitInstanceContainer);
+        SuccessOrExit(err);
+
+        // allocate a new trait instance
+        WEAVE_FAULT_INJECT(FaultInjection::kFault_WDM_TraitInstanceNew, ExitNow(err = WEAVE_ERROR_NO_MEMORY));
+
+        if (SubscriptionEngine::GetInstance()->mNumTraitInfosInPool < SubscriptionEngine::kMaxNumPathGroups)
+        {
+            traitInstance =
+                SubscriptionEngine::GetInstance()->mTraitInfoPool + SubscriptionEngine::GetInstance()->mNumTraitInfosInPool;
+            ++mNumTraitInstances;
+            ++(SubscriptionEngine::GetInstance()->mNumTraitInfosInPool);
+            SYSTEM_STATS_INCREMENT(nl::Weave::System::Stats::kWDM_NumTraits);
+
+            traitInstance->Init();
+        }
+        else
+        {
+            // we run out of trait instances, abort
+            // Note it might help the client understanding what's going on with an error status like
+            // "out of memory" or "internal error", but it's pretty common that a server doesn't disclose
+            // too much internal status to clients
+            SuccessOrExit(err = WEAVE_ERROR_NO_MEMORY);
+        }
+
+
+        traitInstance->mTraitDataHandle  = traitDataHandle;
+        traitInstance->mRequestedVersion = requestedVersion;
+
+        if (NULL == mTraitInstanceList)
+        {
+            // this the first trait instance for this subscription
+            // mNumTraitInstanceList has already be incremented
+            mTraitInstanceList = traitInstance;
+        }
+
+        // TODO (didis) Check if data source is persisted, set to dirty if trait data changed from persisted data
+        WeaveLogDetail(DataManagement, "Handler[%u] Syncing is requested for trait[%u].path[%u]",
+                       SubscriptionEngine::GetInstance()->GetHandlerId(this), traitDataHandle, kRootPropertyPathHandle);
+        err = SubscriptionEngine::GetInstance()->mPublisherCatalog->Locate(traitDataHandle, &dataSource);
+        SuccessOrExit(err);
+        dataSource->SetRootDirty();
+        traitInstance->SetDirty();
+    }
+
+    if (err != WEAVE_END_OF_TLV)
+    {
+        goto exit;
+    }
+
+    err = reader.ExitContainer(traitInstanceArrayContainer);
+    SuccessOrExit(err);
+
+exit:
+    Platform::CriticalSectionExit();
+
+    if (err != WEAVE_NO_ERROR)
+    {
+        WeaveLogError(DataManagement, "Load persistent trait instances error: %d", err);
+    }
+    return err;
+}
+
+WEAVE_ERROR SubscriptionHandler::SerializeSubscriptionState(TLVWriter & writer)
+{
+    WEAVE_ERROR err = WEAVE_NO_ERROR;
+
+    TLV::TLVType container;
+
+    err = writer.StartContainer(TLV::AnonymousTag, TLV::kTLVType_Structure, container);
+    SuccessOrExit(err);
+
+
+    err = writer.Put(TLV::ContextTag(kTag_PersistSubscriptionHandler_PeerNodeId), mPeerNodeId);
+    SuccessOrExit(err);
+    err = writer.Put(TLV::ContextTag(kTag_PersistSubscriptionHandler_SubscriptionId), mSubscriptionId);
+    SuccessOrExit(err);
+    err = writer.Put(TLV::ContextTag(kTag_PersistSubscriptionHandler_LivenessTimeoutMsec), mLivenessTimeoutMsec);
+    SuccessOrExit(err);
+    err = writer.PutBoolean(TLV::ContextTag(kTag_PersistSubscriptionHandler_IsInitiator), mIsInitiator);
+    SuccessOrExit(err);
+    err = writer.PutBoolean(TLV::ContextTag(kTag_PersistSubscriptionHandler_SubscribeToAllEvents), mSubscribeToAllEvents);
+    SuccessOrExit(err);
+
+    err = SerializeTraitInstances(writer);
+    SuccessOrExit(err);
+
+    err = SerializeDeliveredEvents(writer);
+    SuccessOrExit(err);
+
+    err = writer.EndContainer(container);
+    SuccessOrExit(err);
+
+exit:
+
+    if (err != WEAVE_NO_ERROR)
+    {
+        WeaveLogError(DataManagement, "Serialize subscription state error: %d", err);
+    }
+    return err;
+}
+
+WEAVE_ERROR SubscriptionHandler::SerializeTraitInstances(TLVWriter & writer)
+{
+    WEAVE_ERROR err = WEAVE_NO_ERROR;
+
+    Platform::CriticalSectionEnter();
+
+    TLV::TLVType traitInstanceArrayContainer;
+    err = writer.StartContainer(TLV::ContextTag(kTag_PersistTraitInstances), TLV::kTLVType_Array, traitInstanceArrayContainer);
+    SuccessOrExit(err);
+
+    for (size_t i = 0; i < mNumTraitInstances; ++i)
+    {
+        TLV::TLVType traitInstanceContainer;
+
+        err = writer.StartContainer(TLV::AnonymousTag, TLV::kTLVType_Structure, traitInstanceContainer);
+        SuccessOrExit(err);
+        err = writer.Put(TLV::ContextTag(kTag_PersistTraitInstances_TraitDataHandle), mTraitInstanceList[i].mTraitDataHandle);
+        SuccessOrExit(err);
+        err = writer.Put(TLV::ContextTag(kTag_PersistTraitInstances_RequestedVersion), mTraitInstanceList[i].mRequestedVersion);
+        SuccessOrExit(err);
+        err = writer.PutBoolean(TLV::ContextTag(kTag_PersistTraitInstances_IsDirty), mTraitInstanceList[i].mDirty);
+        SuccessOrExit(err);
+
+        err = writer.EndContainer(traitInstanceContainer);
+        SuccessOrExit(err);
+    }
+
+    err = writer.EndContainer(traitInstanceArrayContainer);
+    SuccessOrExit(err);
+
+exit:
+    Platform::CriticalSectionExit();
+
+    if (err != WEAVE_NO_ERROR)
+    {
+        WeaveLogError(DataManagement, "Serialize trait instances error: %d", err);
+    }
+    return err;
+}
+
+WEAVE_ERROR SubscriptionHandler::SerializeDeliveredEvents(TLVWriter & writer)
+{
+    WEAVE_ERROR err = WEAVE_NO_ERROR;
+
+    Platform::CriticalSectionEnter();
+
+    TLV::TLVType container;
+
+    err = writer.StartContainer(TLV::ContextTag(kTag_PersistDeliveredEvent), TLV::kTLVType_Array, container);
+    SuccessOrExit(err);
+
+    for (int importance = kImportanceType_First; importance <= kImportanceType_Last; importance++)
+    {
+        TLV::TLVType deliveredEventContainer;
+        err = writer.StartContainer(TLV::AnonymousTag, TLV::kTLVType_Structure, deliveredEventContainer);
+        SuccessOrExit(err);
+
+        err = writer.Put(TLV::ContextTag(kTag_PersistDeliveredEvent_ImportanceLevel), (uint8_t)importance);
+        SuccessOrExit(err);
+
+        err = writer.Put(TLV::ContextTag(kTag_PersistDeliveredEvent_EventId), mDeliveredEvents[static_cast<uint32_t>(importance) - static_cast<uint32_t>(kImportanceType_First)]);
+        SuccessOrExit(err);
+
+        err = writer.EndContainer(deliveredEventContainer);
+        SuccessOrExit(err);
+    }
+
+    err = writer.EndContainer(container);
+    SuccessOrExit(err);
+
+exit:
+    Platform::CriticalSectionExit();
+
+    if (err != WEAVE_NO_ERROR)
+    {
+        WeaveLogError(DataManagement, "Serialize delivered event id error: %d", err);
+    }
+    return err;
+}
+
+WEAVE_ERROR SubscriptionHandler::LoadDeliveredEvents(TLVReader & reader)
+{
+    WEAVE_ERROR err = WEAVE_NO_ERROR;
+
+    Platform::CriticalSectionEnter();
+
+    TLV::TLVType container;
+
+    err = reader.Next(TLV::kTLVType_Array, TLV::ContextTag(kTag_PersistDeliveredEvent));
+    SuccessOrExit(err);
+    err = reader.EnterContainer(container);
+    SuccessOrExit(err);
+
+    for (int importance = kImportanceType_First; importance <= kImportanceType_Last; importance++)
+    {
+        TLV::TLVType deliveredEventContainer;
+        uint8_t persistedImportance;
+
+        err = reader.Next(TLV::kTLVType_Structure, TLV::AnonymousTag);
+        SuccessOrExit(err);
+        err = reader.EnterContainer(deliveredEventContainer);
+        SuccessOrExit(err);
+
+        err = reader.Next(TLV::kTLVType_UnsignedInteger, TLV::ContextTag(kTag_PersistDeliveredEvent_ImportanceLevel));
+        SuccessOrExit(err);
+        err = reader.Get(persistedImportance);
+        SuccessOrExit(err);
+        VerifyOrExit(persistedImportance == importance, err = WEAVE_ERROR_PERSISTED_STORAGE_FAIL);
+
+        err = reader.Next(TLV::kTLVType_UnsignedInteger, TLV::ContextTag(kTag_PersistDeliveredEvent_EventId));
+        SuccessOrExit(err);
+        err = reader.Get(mDeliveredEvents[static_cast<uint32_t>(importance) - static_cast<uint32_t>(kImportanceType_First)]);
+        SuccessOrExit(err);
+
+        err = reader.ExitContainer(deliveredEventContainer);
+        SuccessOrExit(err);
+    }
+
+    err = reader.ExitContainer(container);
+    SuccessOrExit(err);
+
+exit:
+    Platform::CriticalSectionExit();
+    if (err != WEAVE_NO_ERROR)
+    {
+        WeaveLogError(DataManagement, "Load persistent delivered events error: %d", err);
+    }
+    return err;
+}
+#endif // WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+
 }; // namespace WeaveMakeManagedNamespaceIdentifier(DataManagement, kWeaveManagedNamespaceDesignation_Current)
 }; // namespace Profiles
 }; // namespace Weave
diff --git a/src/lib/profiles/data-management/Current/SubscriptionHandler.h b/src/lib/profiles/data-management/Current/SubscriptionHandler.h
index ccd09d4..90fdd72 100644
--- a/src/lib/profiles/data-management/Current/SubscriptionHandler.h
+++ b/src/lib/profiles/data-management/Current/SubscriptionHandler.h
@@ -217,6 +217,30 @@
         kState_SubscriptionInfoValid_End         = kState_Canceling,
     };
 
+#if WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+    /**
+     * @brief
+     *  Tags for the persistent subscription data
+     */
+    enum
+    {
+        kTag_PersistSubscriptionHandler_PeerNodeId             = 1,
+        kTag_PersistSubscriptionHandler_SubscriptionId         = 2,
+        kTag_PersistSubscriptionHandler_LivenessTimeoutMsec    = 3,
+        kTag_PersistSubscriptionHandler_IsInitiator            = 4,
+        kTag_PersistSubscriptionHandler_SubscribeToAllEvents   = 5,
+
+        kTag_PersistTraitInstances                             = 6,
+        kTag_PersistTraitInstances_TraitDataHandle             = 7,
+        kTag_PersistTraitInstances_RequestedVersion            = 8,
+        kTag_PersistTraitInstances_IsDirty                     = 9,
+
+        kTag_PersistDeliveredEvent                             = 10,
+        kTag_PersistDeliveredEvent_ImportanceLevel             = 11,
+        kTag_PersistDeliveredEvent_EventId                     = 12
+    };
+#endif // WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+
     HandlerState mCurrentState;
 
     bool IsNotifiable(void)
@@ -260,6 +284,9 @@
     // TODO: WEAV-1426 in this incarnation, we do not account for event aggregation.
     event_id_t mSelfVendedEvents[kImportanceType_Last - kImportanceType_First + 1];
     event_id_t mLastScheduledEventId[kImportanceType_Last - kImportanceType_First + 1];
+#if WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+    event_id_t mDeliveredEvents[kImportanceType_Last - kImportanceType_First + 1];
+#endif // WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
     ImportanceType mCurrentImportance;
 
     // The counter here tracks the number of event bytes offloaded to
@@ -298,6 +325,16 @@
     ImportanceType FindNextImportanceForTransfer(void);
     WEAVE_ERROR SetEventLogEndpoint(LoggingManagement & logger);
 
+#if WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+    WEAVE_ERROR LoadFromPersistedState(Binding * const apBinding, void * const apAppState, EventCallback const aEventCallback, TLVReader & reader);
+    WEAVE_ERROR SerializeSubscriptionState(TLVWriter & writer);
+    WEAVE_ERROR LoadSubscriptionState(TLVReader & reader);
+    WEAVE_ERROR SerializeTraitInstances(TLVWriter & writer);
+    WEAVE_ERROR LoadTraitInstances(TLVReader & reader);
+    WEAVE_ERROR SerializeDeliveredEvents(TLVWriter & writer);
+    WEAVE_ERROR LoadDeliveredEvents(TLVReader & reader);
+#endif // WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+
 #if WDM_ENABLE_SUBSCRIPTION_CANCEL
     WEAVE_ERROR Cancel(void);
     void CancelRequestHandler(nl::Weave::ExchangeContext * aEC, const nl::Inet::IPPacketInfo * aPktInfo,
@@ -312,6 +349,10 @@
     inline WEAVE_ERROR ParseSubscriptionId(SubscribeRequest::Parser & aRequest, uint32_t & aRejectReasonProfileId,
                                            uint16_t & aRejectReasonStatusCode, const uint64_t aRandomNumber);
 
+#if WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+    void UpdateDeliveredEvents(ImportanceType importance);
+#endif // WEAVE_CONFIG_PERSIST_SUBSCRIPTION_STATE
+
     static void BindingEventCallback(void * const apAppState, const Binding::EventType aEvent,
                                      const Binding::InEventParam & aInParam, Binding::OutEventParam & aOutParam);
     static void OnTimerCallback(System::Layer * aSystemLayer, void * aAppState, System::Error aErrorCode);