diff --git a/src/coins.cpp b/src/coins.cpp
index 01eefddde..96820b420 100644
--- a/src/coins.cpp
+++ b/src/coins.cpp
@@ -36,6 +36,7 @@ bool CCoinsViewBacked::BatchWrite(CCoinsMap& mapCoins, const uint256& hashBlock,
 CCoinsViewCursor *CCoinsViewBacked::Cursor() const { return base->Cursor(); }
 size_t CCoinsViewBacked::EstimateSize() const { return base->EstimateSize(); }
 mw::ICoinsView::Ptr CCoinsViewBacked::GetMWEBView() const { return base->GetMWEBView(); }
+bool CCoinsViewBacked::GetMWEBCoin(const mw::Hash& output_id, Output& coin) const { return base->GetMWEBCoin(output_id, coin); }
 
 SaltedOutpointHasher::SaltedOutpointHasher() : k0(GetRand(std::numeric_limits<uint64_t>::max())), k1(GetRand(std::numeric_limits<uint64_t>::max())) {}
 
@@ -148,20 +149,44 @@ const Coin& CCoinsViewCache::AccessCoin(const COutPoint &outpoint) const {
 
 bool CCoinsViewCache::HaveCoin(const OutputIndex& index) const {
     if (index.type() == typeid(mw::Hash)) {
-        return GetMWEBView()->HasCoin(boost::get<mw::Hash>(index));
+        const mw::Hash& output_id = boost::get<mw::Hash>(index);
+        if (GetMWEBCacheView()->HasCoinInCache(output_id)) {
+            return true;
+        }
+
+        if (GetMWEBCacheView()->HasSpendInCache(output_id)) {
+            return false;
+        }
+
+        return base->HaveCoin(index);
     } else {
         CCoinsMap::const_iterator it = FetchCoin(boost::get<COutPoint>(index));
         return (it != cacheCoins.end() && !it->second.coin.IsSpent());
     }
 }
 
+bool CCoinsViewCache::GetMWEBCoin(const mw::Hash& output_id, Output& coin) const {
+    if (GetMWEBCacheView()->HasCoinInCache(output_id)) {
+        std::vector<UTXO::CPtr> utxos = GetMWEBCacheView()->GetUTXOs(output_id);
+        assert(!utxos.empty());
+        coin = utxos.front()->GetOutput();
+        return true;
+    }
+
+    if (GetMWEBCacheView()->HasSpendInCache(output_id)) {
+        return false;
+    }
+
+    return base->GetMWEBCoin(output_id, coin);
+}
+
 bool CCoinsViewCache::HaveCoinInCache(const OutputIndex& index) const {
-    if (index.type() == typeid(mw::Hash)) {
-        return GetMWEBView()->HasCoinInCache(boost::get<mw::Hash>(index));
-    } else {
+    if (index.type() == typeid(COutPoint)) {
         CCoinsMap::const_iterator it = cacheCoins.find(boost::get<COutPoint>(index));
         return (it != cacheCoins.end() && !it->second.coin.IsSpent());
     }
+
+    return false;
 }
 
 uint256 CCoinsViewCache::GetBestBlock() const {
diff --git a/src/coins.h b/src/coins.h
index b67d92e8f..dcd81cfe9 100644
--- a/src/coins.h
+++ b/src/coins.h
@@ -222,6 +222,8 @@ public:
     virtual size_t EstimateSize() const { return 0; }
 
     virtual mw::ICoinsView::Ptr GetMWEBView() const { return nullptr; }
+    
+    virtual bool GetMWEBCoin(const mw::Hash& output_id, Output& coin) const { return false; }
 };
 
 
@@ -242,6 +244,7 @@ public:
     CCoinsViewCursor *Cursor() const override;
     size_t EstimateSize() const override;
     mw::ICoinsView::Ptr GetMWEBView() const override;
+    bool GetMWEBCoin(const mw::Hash& output_id, Output& coin) const override;
 };
 
 
@@ -283,6 +286,8 @@ public:
     mw::ICoinsView::Ptr GetMWEBView() const final { return mweb_view; }
     mw::CoinsViewCache::Ptr GetMWEBCacheView() const { return mweb_view; }
 
+    bool GetMWEBCoin(const mw::Hash& output_id, Output& coin) const final;
+
     /**
      * Check if we have the given utxo already loaded in this cache.
      * The semantics are the same as HaveCoin(), but no calls to
diff --git a/src/consensus/tx_verify.cpp b/src/consensus/tx_verify.cpp
index 45afa6e51..d74511d66 100644
--- a/src/consensus/tx_verify.cpp
+++ b/src/consensus/tx_verify.cpp
@@ -214,13 +214,12 @@ bool Consensus::CheckTxInputs(const CTransaction& tx, TxValidationState& state,
     // MWEB
     if (tx.HasMWEBTx()) {
         for (const Input& input : tx.mweb_tx.m_transaction->GetInputs()) {
-            auto utxos = inputs.GetMWEBView()->GetUTXOs(input.GetOutputID());
-            if (utxos.empty()) {
+            Output utxo;
+            if (!inputs.GetMWEBCoin(input.GetOutputID(), utxo)) {
                 return state.Invalid(TxValidationResult::TX_CONSENSUS, "bad-txns-inputs-missing",
                     strprintf("%s: MWEB inputs missing", __func__));
             }
 
-            const Output& utxo = utxos.front()->GetOutput();
             if (utxo.GetReceiverPubKey() != input.GetOutputPubKey() || utxo.GetCommitment() != input.GetCommitment()) {
                 return state.Invalid(TxValidationResult::TX_CONSENSUS, "bad-txns-input-mismatch",
                                      strprintf("%s: MWEB input doesn't match UTXO", __func__));
diff --git a/src/init.cpp b/src/init.cpp
index 87c512718..6674f20ea 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -1199,7 +1199,7 @@ bool AppInitParameterInteraction(const ArgsManager& args)
     if (args.GetArg("-rpcserialversion", DEFAULT_RPC_SERIALIZE_VERSION) < 0)
         return InitError(Untranslated("rpcserialversion must be non-negative."));
 
-    if (args.GetArg("-rpcserialversion", DEFAULT_RPC_SERIALIZE_VERSION) > 1)
+    if (args.GetArg("-rpcserialversion", DEFAULT_RPC_SERIALIZE_VERSION) > 2)
         return InitError(Untranslated("Unknown rpcserialversion requested."));
 
     nMaxTipAge = args.GetArg("-maxtipage", DEFAULT_MAX_TIP_AGE);
diff --git a/src/libmw/include/mw/exceptions/ValidationException.h b/src/libmw/include/mw/exceptions/ValidationException.h
index 432436a3c..cd70fb8fe 100644
--- a/src/libmw/include/mw/exceptions/ValidationException.h
+++ b/src/libmw/include/mw/exceptions/ValidationException.h
@@ -19,7 +19,8 @@ enum class EConsensusError
     MMR_MISMATCH,
     UTXO_MISSING,
     UTXO_MISMATCH,
-    NOT_SORTED
+    NOT_SORTED,
+    BAD_STATE
 };
 
 class ValidationException : public LTCException
@@ -67,6 +68,8 @@ private:
                 return "UTXO_MISMATCH";
             case EConsensusError::NOT_SORTED:
                 return "NOT_SORTED";
+            case EConsensusError::BAD_STATE:
+                return "BAD_STATE";
         }
 
         return "UNKNOWN";
diff --git a/src/libmw/include/mw/node/CoinsView.h b/src/libmw/include/mw/node/CoinsView.h
index d3825d4a2..f1bbbe7f1 100644
--- a/src/libmw/include/mw/node/CoinsView.h
+++ b/src/libmw/include/mw/node/CoinsView.h
@@ -40,7 +40,7 @@ public:
     virtual bool IsCache() const noexcept = 0;
 
     // Virtual functions
-    virtual std::vector<UTXO::CPtr> GetUTXOs(const mw::Hash& output_id) const = 0;
+    virtual UTXO::CPtr GetUTXO(const mw::Hash& output_id) const = 0;
     virtual void WriteBatch(
         const mw::DBBatch::UPtr& pBatch,
         const CoinsViewUpdates& updates,
@@ -55,7 +55,7 @@ public:
     /// </summary>
     /// <param name="output_id">The output ID of the UTXO to look for.</param>
     /// <returns>True if there's a matching unspent coin. Otherwise, false.</returns>
-    bool HasCoin(const mw::Hash& output_id) const noexcept { return !GetUTXOs(output_id).empty(); }
+    bool HasCoin(const mw::Hash& output_id) const noexcept { return GetUTXO(output_id) != nullptr; }
 
     /// <summary>
     /// Checks if there's a unspent coin with a matching commitment in the view that has not been flushed to the parent.
@@ -85,7 +85,7 @@ public:
 
     bool IsCache() const noexcept final { return true; }
 
-    std::vector<UTXO::CPtr> GetUTXOs(const mw::Hash& output_id) const noexcept final;
+    UTXO::CPtr GetUTXO(const mw::Hash& output_id) const noexcept final;
 
     /// <summary>
     /// Validates and connects the block to the end of the chain.
@@ -96,6 +96,8 @@ public:
     /// <throws>ValidationException if consensus rules are not met.</throws>
     mw::BlockUndo::CPtr ApplyBlock(const mw::Block::CPtr& pBlock);
 
+    void AddTx(const mw::Transaction::CPtr& pTx);
+
     /// <summary>
     /// Removes a block from the end of the chain.
     /// </summary>
@@ -119,6 +121,7 @@ public:
     mw::Block::Ptr BuildNextBlock(const uint64_t height, const std::vector<mw::Transaction::CPtr>& transactions);
 
     bool HasCoinInCache(const mw::Hash& output_id) const noexcept final;
+    bool HasSpendInCache(const mw::Hash& output_id) const noexcept;
 
     ILeafSet::Ptr GetLeafSet() const noexcept final { return m_pLeafSet; }
     IMMR::Ptr GetOutputPMMR() const noexcept final { return m_pOutputPMMR; }
@@ -148,7 +151,7 @@ public:
 
     bool IsCache() const noexcept final { return false; }
 
-    std::vector<UTXO::CPtr> GetUTXOs(const mw::Hash& output_id) const final;
+    UTXO::CPtr GetUTXO(const mw::Hash& output_id) const final;
     void WriteBatch(
         const mw::DBBatch::UPtr& pBatch,
         const CoinsViewUpdates& updates,
@@ -174,7 +177,7 @@ private:
     void AddUTXO(CoinDB& coinDB, const Output& output);
     void AddUTXO(CoinDB& coinDB, const UTXO::CPtr& pUTXO);
     void SpendUTXO(CoinDB& coinDB, const mw::Hash& output_id);
-    std::vector<UTXO::CPtr> GetUTXOs(const CoinDB& coinDB, const mw::Hash& output_id) const;
+    UTXO::CPtr GetUTXO(const CoinDB& coinDB, const mw::Hash& output_id) const;
 
     LeafSet::Ptr m_pLeafSet;
     PMMR::Ptr m_pOutputPMMR;
diff --git a/src/libmw/src/node/BlockBuilder.cpp b/src/libmw/src/node/BlockBuilder.cpp
index 951c2f90d..9b5cf1b30 100644
--- a/src/libmw/src/node/BlockBuilder.cpp
+++ b/src/libmw/src/node/BlockBuilder.cpp
@@ -62,7 +62,7 @@ bool BlockBuilder::AddTransaction(const Transaction::CPtr& pTransaction, const s
 
     // Make sure all inputs are available.
     for (const Input& input : pTransaction->GetInputs()) {
-        if (m_pCoinsView->GetUTXOs(input.GetOutputID()).empty()) {
+        if (!m_pCoinsView->HasCoin(input.GetOutputID())) {
             LOG_ERROR_F("Input {} not found on chain", input.GetOutputID());
             return false;
         }
@@ -70,7 +70,7 @@ bool BlockBuilder::AddTransaction(const Transaction::CPtr& pTransaction, const s
 
     // Make sure no duplicate outputs already on chain.
     for (const Output& output : pTransaction->GetOutputs()) {
-        if (!m_pCoinsView->GetUTXOs(output.GetOutputID()).empty()) {
+        if (m_pCoinsView->HasCoin(output.GetOutputID())) {
             LOG_ERROR_F("Output {} already on chain", output.GetOutputID());
             return false;
         }
diff --git a/src/libmw/src/node/CoinsViewCache.cpp b/src/libmw/src/node/CoinsViewCache.cpp
index 7bf004894..9069f8a64 100644
--- a/src/libmw/src/node/CoinsViewCache.cpp
+++ b/src/libmw/src/node/CoinsViewCache.cpp
@@ -16,21 +16,22 @@ CoinsViewCache::CoinsViewCache(const ICoinsView::Ptr& pBase)
       m_pOutputPMMR(std::make_unique<PMMRCache>(pBase->GetOutputPMMR())),
       m_pUpdates(std::make_shared<CoinsViewUpdates>()) {}
 
-std::vector<UTXO::CPtr> CoinsViewCache::GetUTXOs(const mw::Hash& output_id) const noexcept
+UTXO::CPtr CoinsViewCache::GetUTXO(const mw::Hash& output_id) const noexcept
 {
-    std::vector<UTXO::CPtr> utxos = m_pBase->GetUTXOs(output_id);
+    UTXO::CPtr pUTXO = m_pBase->GetUTXO(output_id);
 
     std::vector<CoinAction> actions = m_pUpdates->GetActions(output_id);
     for (const CoinAction& action : actions) {
         if (action.pUTXO != nullptr) {
-            utxos.push_back(action.pUTXO);
+            // MW: TODO - Don't allow having more than one UTXO with output_id at a time
+            pUTXO = action.pUTXO;
         } else {
-            assert(!utxos.empty());
-            utxos.pop_back();
+            assert(pUTXO != nullptr);
+            pUTXO = nullptr;
         }
     }
 
-    return utxos;
+    return pUTXO;
 }
 
 mw::BlockUndo::CPtr CoinsViewCache::ApplyBlock(const mw::Block::CPtr& pBlock)
@@ -72,6 +73,25 @@ mw::BlockUndo::CPtr CoinsViewCache::ApplyBlock(const mw::Block::CPtr& pBlock)
     return std::make_shared<mw::BlockUndo>(pPreviousHeader, std::move(coinsSpent), std::move(coinsAdded));
 }
 
+static const uint32_t MEMPOOL_HEIGHT = 0x7FFFFFFF;
+
+void CoinsViewCache::AddTx(const mw::Transaction::CPtr& pTx)
+{
+    std::for_each(
+        pTx->GetInputs().cbegin(), pTx->GetInputs().cend(),
+        [this](const Input& input) {
+            SpendUTXO(input.GetOutputID());
+        }
+    );
+
+    std::for_each(
+        pTx->GetOutputs().cbegin(), pTx->GetOutputs().cend(),
+        [this](const Output& output) {
+            AddUTXO(MEMPOOL_HEIGHT, output);
+        }
+    );
+}
+
 void CoinsViewCache::UndoBlock(const mw::BlockUndo::CPtr& pUndo)
 {
     assert(pUndo != nullptr);
@@ -164,7 +184,17 @@ bool CoinsViewCache::HasCoinInCache(const mw::Hash& output_id) const noexcept
 {
     std::vector<CoinAction> actions = m_pUpdates->GetActions(output_id);
     if (!actions.empty()) {
-        return actions.back().pUTXO != nullptr;
+        return !actions.back().IsSpend();
+    }
+
+    return false;
+}
+
+bool CoinsViewCache::HasSpendInCache(const mw::Hash& output_id) const noexcept
+{
+    std::vector<CoinAction> actions = m_pUpdates->GetActions(output_id);
+    if (!actions.empty()) {
+        return actions.back().IsSpend();
     }
 
     return false;
@@ -182,24 +212,25 @@ void CoinsViewCache::AddUTXO(const uint64_t header_height, const Output& output)
 
 UTXO CoinsViewCache::SpendUTXO(const mw::Hash& output_id)
 {
-    std::vector<UTXO::CPtr> utxos = GetUTXOs(output_id);
-    if (utxos.empty() || !m_pLeafSet->Contains(utxos.back()->GetLeafIndex())) {
+    UTXO::CPtr pUTXO = GetUTXO(output_id);
+    if (pUTXO == nullptr || !m_pLeafSet->Contains(pUTXO->GetLeafIndex())) {
         ThrowValidation(EConsensusError::UTXO_MISSING);
     }
 
-    m_pLeafSet->Remove(utxos.back()->GetLeafIndex());
+    m_pLeafSet->Remove(pUTXO->GetLeafIndex());
     m_pUpdates->SpendUTXO(output_id);
 
-    return *utxos.back();
+    return *pUTXO;
 }
 
 void CoinsViewCache::WriteBatch(const std::unique_ptr<mw::DBBatch>&, const CoinsViewUpdates& updates, const mw::Header::CPtr& pHeader)
 {
     SetBestHeader(pHeader);
-
+     
     for (const auto& actions : updates.GetActions()) {
         const mw::Hash& output_id = actions.first;
         for (const auto& action : actions.second) {
+            // MW: TODO - This is probably a good place to make sure there's no duplicate outputs
             if (action.IsSpend()) {
                 m_pUpdates->SpendUTXO(output_id);
             } else {
diff --git a/src/libmw/src/node/CoinsViewDB.cpp b/src/libmw/src/node/CoinsViewDB.cpp
index 5486673fd..a963d18ec 100644
--- a/src/libmw/src/node/CoinsViewDB.cpp
+++ b/src/libmw/src/node/CoinsViewDB.cpp
@@ -26,20 +26,20 @@ CoinsViewDB::Ptr CoinsViewDB::Open(
     return std::shared_ptr<CoinsViewDB>(pView);
 }
 
-std::vector<UTXO::CPtr> CoinsViewDB::GetUTXOs(const mw::Hash& output_id) const
+UTXO::CPtr CoinsViewDB::GetUTXO(const mw::Hash& output_id) const
 {
     CoinDB coinDB(GetDatabase().get(), nullptr);
-    return GetUTXOs(coinDB, output_id);
+    return GetUTXO(coinDB, output_id);
 }
 
-std::vector<UTXO::CPtr> CoinsViewDB::GetUTXOs(const CoinDB& coinDB, const mw::Hash& output_id) const
+UTXO::CPtr CoinsViewDB::GetUTXO(const CoinDB& coinDB, const mw::Hash& output_id) const
 {
     std::vector<uint8_t> value;
 
     auto utxos_by_hash = coinDB.GetUTXOs({output_id});
     auto iter = utxos_by_hash.find(output_id);
     if (iter != utxos_by_hash.cend()) {
-        return { iter->second };
+        return iter->second;
     }
 
     return {};
@@ -55,16 +55,13 @@ void CoinsViewDB::AddUTXO(CoinDB& coinDB, const Output& output)
 
 void CoinsViewDB::AddUTXO(CoinDB& coinDB, const UTXO::CPtr& pUTXO)
 {
-    std::vector<UTXO::CPtr> utxos = GetUTXOs(coinDB, pUTXO->GetOutputID());
-    utxos.push_back(pUTXO);
-
     coinDB.AddUTXOs(std::vector<UTXO::CPtr>{ pUTXO });
 }
 
 void CoinsViewDB::SpendUTXO(CoinDB& coinDB, const mw::Hash& output_id)
 {
-    std::vector<UTXO::CPtr> utxos = GetUTXOs(coinDB, output_id);
-    if (utxos.empty()) {
+    UTXO::CPtr pUTXO = GetUTXO(coinDB, output_id);
+    if (pUTXO == nullptr) {
 		ThrowValidation(EConsensusError::UTXO_MISSING);
     }
 
diff --git a/src/libmw/test/tests/node/Test_MineChain.cpp b/src/libmw/test/tests/node/Test_MineChain.cpp
index 8269f01bf..5a6144813 100644
--- a/src/libmw/test/tests/node/Test_MineChain.cpp
+++ b/src/libmw/test/tests/node/Test_MineChain.cpp
@@ -30,8 +30,8 @@ BOOST_AUTO_TEST_CASE(MineChain)
     pCachedView->ApplyBlock(block1.GetBlock());
 
     const auto& block1_tx1_output1 = block1_tx1.GetOutputs()[0];
-    BOOST_REQUIRE(pDBView->GetUTXOs(block1_tx1_output1.GetOutputID()).empty());
-    BOOST_REQUIRE(pCachedView->GetUTXOs(block1_tx1_output1.GetOutputID()).size() == 1);
+    BOOST_REQUIRE(pDBView->GetUTXO(block1_tx1_output1.GetOutputID()) == nullptr);
+    BOOST_REQUIRE(pCachedView->GetUTXO(block1_tx1_output1.GetOutputID()) != nullptr);
 
     ///////////////////////
     // Mine Block 2
@@ -42,8 +42,8 @@ BOOST_AUTO_TEST_CASE(MineChain)
     pCachedView->ApplyBlock(block2.GetBlock());
 
     const auto& block2_tx1_output1 = block2_tx1.GetOutputs()[0];
-    BOOST_REQUIRE(pDBView->GetUTXOs(block2_tx1_output1.GetOutputID()).empty());
-    BOOST_REQUIRE(pCachedView->GetUTXOs(block2_tx1_output1.GetOutputID()).size() == 1);
+    BOOST_REQUIRE(pDBView->GetUTXO(block2_tx1_output1.GetOutputID()) == nullptr);
+    BOOST_REQUIRE(pCachedView->GetUTXO(block2_tx1_output1.GetOutputID()) != nullptr);
 
     ///////////////////////
     // Flush View
@@ -52,10 +52,10 @@ BOOST_AUTO_TEST_CASE(MineChain)
     pCachedView->Flush(pBatch);
     pBatch->Commit();
 
-    BOOST_REQUIRE(pDBView->GetUTXOs(block1_tx1_output1.GetOutputID()).size() == 1);
-    BOOST_REQUIRE(pCachedView->GetUTXOs(block1_tx1_output1.GetOutputID()).size() == 1);
-    BOOST_REQUIRE(pDBView->GetUTXOs(block2_tx1_output1.GetOutputID()).size() == 1);
-    BOOST_REQUIRE(pCachedView->GetUTXOs(block2_tx1_output1.GetOutputID()).size() == 1);
+    BOOST_REQUIRE(pDBView->GetUTXO(block1_tx1_output1.GetOutputID()) != nullptr);
+    BOOST_REQUIRE(pCachedView->GetUTXO(block1_tx1_output1.GetOutputID()) != nullptr);
+    BOOST_REQUIRE(pDBView->GetUTXO(block2_tx1_output1.GetOutputID()) != nullptr);
+    BOOST_REQUIRE(pCachedView->GetUTXO(block2_tx1_output1.GetOutputID()) != nullptr);
 }
 
 BOOST_AUTO_TEST_SUITE_END()
\ No newline at end of file
diff --git a/src/libmw/test/tests/node/Test_Reorg.cpp b/src/libmw/test/tests/node/Test_Reorg.cpp
index 3505f3382..2e21633e9 100644
--- a/src/libmw/test/tests/node/Test_Reorg.cpp
+++ b/src/libmw/test/tests/node/Test_Reorg.cpp
@@ -30,8 +30,8 @@ BOOST_AUTO_TEST_CASE(ReorgChain)
     pCachedView->ApplyBlock(block1.GetBlock());
 
     const auto& block1_tx1_output1 = block1_tx1.GetOutputs()[0];
-    BOOST_REQUIRE(pDBView->GetUTXOs(block1_tx1_output1.GetOutputID()).empty());
-    BOOST_REQUIRE(pCachedView->GetUTXOs(block1_tx1_output1.GetOutputID()).size() == 1);
+    BOOST_REQUIRE(pDBView->GetUTXO(block1_tx1_output1.GetOutputID()) == nullptr);
+    BOOST_REQUIRE(pCachedView->GetUTXO(block1_tx1_output1.GetOutputID()) != nullptr);
 
     ///////////////////////
     // Mine Block 2
@@ -42,15 +42,15 @@ BOOST_AUTO_TEST_CASE(ReorgChain)
     mw::BlockUndo::CPtr undoBlock2 = pCachedView->ApplyBlock(block2.GetBlock());
 
     const auto& block2_tx1_output1 = block2_tx1.GetOutputs()[0];
-    BOOST_REQUIRE(pDBView->GetUTXOs(block2_tx1_output1.GetOutputID()).empty());
-    BOOST_REQUIRE(pCachedView->GetUTXOs(block2_tx1_output1.GetOutputID()).size() == 1);
+    BOOST_REQUIRE(pDBView->GetUTXO(block2_tx1_output1.GetOutputID()) == nullptr);
+    BOOST_REQUIRE(pCachedView->GetUTXO(block2_tx1_output1.GetOutputID()) != nullptr);
 
     ///////////////////////
     // Disconnect Block 2
     ///////////////////////
     pCachedView->UndoBlock(undoBlock2);
-    BOOST_REQUIRE(pCachedView->GetUTXOs(block1_tx1_output1.GetOutputID()).size() == 1);
-    BOOST_REQUIRE(pCachedView->GetUTXOs(block2_tx1_output1.GetOutputID()).empty());
+    BOOST_REQUIRE(pCachedView->GetUTXO(block1_tx1_output1.GetOutputID()) != nullptr);
+    BOOST_REQUIRE(pCachedView->GetUTXO(block2_tx1_output1.GetOutputID()) == nullptr);
     miner.Rewind(1);
 
     ///////////////////////
@@ -62,8 +62,8 @@ BOOST_AUTO_TEST_CASE(ReorgChain)
     pCachedView->ApplyBlock(block3.GetBlock());
 
     const auto& block3_tx1_output1 = block3_tx1.GetOutputs()[0];
-    BOOST_REQUIRE(pDBView->GetUTXOs(block3_tx1_output1.GetOutputID()).empty());
-    BOOST_REQUIRE(pCachedView->GetUTXOs(block3_tx1_output1.GetOutputID()).size() == 1);
+    BOOST_REQUIRE(pDBView->GetUTXO(block3_tx1_output1.GetOutputID()) == nullptr);
+    BOOST_REQUIRE(pCachedView->GetUTXO(block3_tx1_output1.GetOutputID()) != nullptr);
 
     ///////////////////////
     // Flush View
@@ -72,12 +72,12 @@ BOOST_AUTO_TEST_CASE(ReorgChain)
     pCachedView->Flush(pBatch);
     pBatch->Commit();
 
-    BOOST_REQUIRE(pDBView->GetUTXOs(block1_tx1_output1.GetOutputID()).size() == 1);
-    BOOST_REQUIRE(pCachedView->GetUTXOs(block1_tx1_output1.GetOutputID()).size() == 1);
-    BOOST_REQUIRE(pDBView->GetUTXOs(block2_tx1_output1.GetOutputID()).empty());
-    BOOST_REQUIRE(pCachedView->GetUTXOs(block2_tx1_output1.GetOutputID()).empty());
-    BOOST_REQUIRE(pDBView->GetUTXOs(block3_tx1_output1.GetOutputID()).size() == 1);
-    BOOST_REQUIRE(pCachedView->GetUTXOs(block3_tx1_output1.GetOutputID()).size() == 1);
+    BOOST_REQUIRE(pDBView->GetUTXO(block1_tx1_output1.GetOutputID()) != nullptr);
+    BOOST_REQUIRE(pCachedView->GetUTXO(block1_tx1_output1.GetOutputID()) != nullptr);
+    BOOST_REQUIRE(pDBView->GetUTXO(block2_tx1_output1.GetOutputID()) == nullptr);
+    BOOST_REQUIRE(pCachedView->GetUTXO(block2_tx1_output1.GetOutputID()) == nullptr);
+    BOOST_REQUIRE(pDBView->GetUTXO(block3_tx1_output1.GetOutputID()) != nullptr);
+    BOOST_REQUIRE(pCachedView->GetUTXO(block3_tx1_output1.GetOutputID()) != nullptr);
 }
 
 BOOST_AUTO_TEST_SUITE_END()
\ No newline at end of file
diff --git a/src/mweb/mweb_models.h b/src/mweb/mweb_models.h
index 6e53eff2f..9d472d9bc 100644
--- a/src/mweb/mweb_models.h
+++ b/src/mweb/mweb_models.h
@@ -195,6 +195,22 @@ struct Tx {
         return IsNull() ? 0 : m_transaction->GetLockHeight();
     }
 
+    bool GetOutput(const mw::Hash& output_id, Output& output) const noexcept
+    {
+        if (IsNull()) {
+            return false;
+        }
+
+        for (const Output& o : m_transaction->GetOutputs()) {
+            if (o.GetOutputID() == output_id) {
+                output = o;
+                return true;
+            }
+        }
+
+        return false;
+    }
+
     SERIALIZE_METHODS(Tx, obj)
     {
         READWRITE(WrapOptionalPtr(obj.m_transaction));
diff --git a/src/node/transaction.cpp b/src/node/transaction.cpp
index 97d5aad8e..b244bf3ba 100644
--- a/src/node/transaction.cpp
+++ b/src/node/transaction.cpp
@@ -42,11 +42,8 @@ TransactionError BroadcastTransaction(NodeContext& node, const CTransactionRef t
     // If the transaction is already confirmed in the chain, don't do anything
     // and return early.
     CCoinsViewCache &view = ::ChainstateActive().CoinsTip();
-    for (size_t o = 0; o < tx->vout.size(); o++) {
-        const Coin& existingCoin = view.AccessCoin(COutPoint(hashTx, o));
-        // IsSpent doesn't mean the coin is spent, it means the output doesn't exist.
-        // So if the output does exist, then this transaction exists in the chain.
-        if (!existingCoin.IsSpent()) return TransactionError::ALREADY_IN_CHAIN;
+    for (const CTxOutput& o : tx->GetOutputs()) {
+        if (view.HaveCoin(o.GetIndex())) return TransactionError::ALREADY_IN_CHAIN;
     }
     if (!node.mempool->exists(hashTx)) {
         // Transaction is not already in the mempool.
diff --git a/src/rpc/server.cpp b/src/rpc/server.cpp
index 953e76734..f45da07e3 100644
--- a/src/rpc/server.cpp
+++ b/src/rpc/server.cpp
@@ -509,8 +509,13 @@ void RPCRunLater(const std::string& name, std::function<void()> func, int64_t nS
 int RPCSerializationFlags()
 {
     int flag = 0;
-    if (gArgs.GetArg("-rpcserialversion", DEFAULT_RPC_SERIALIZE_VERSION) == 0)
+    unsigned int rpc_serialize_version = gArgs.GetArg("-rpcserialversion", DEFAULT_RPC_SERIALIZE_VERSION);
+    if (rpc_serialize_version == 0) {
         flag |= SERIALIZE_TRANSACTION_NO_WITNESS | SERIALIZE_NO_MWEB;
+    } else if (rpc_serialize_version == 1) {
+        flag |= SERIALIZE_NO_MWEB;
+    }
+
     return flag;
 }
 
diff --git a/src/rpc/server.h b/src/rpc/server.h
index b2358ac5b..4b3102cd6 100644
--- a/src/rpc/server.h
+++ b/src/rpc/server.h
@@ -17,7 +17,7 @@
 
 #include <univalue.h>
 
-static const unsigned int DEFAULT_RPC_SERIALIZE_VERSION = 1;
+static const unsigned int DEFAULT_RPC_SERIALIZE_VERSION = 2;
 
 class CRPCCommand;
 
diff --git a/src/txdb.cpp b/src/txdb.cpp
index ace536515..ca20ac5c7 100644
--- a/src/txdb.cpp
+++ b/src/txdb.cpp
@@ -67,6 +67,16 @@ bool CCoinsViewDB::HaveCoin(const OutputIndex& index) const {
     }
 }
 
+bool CCoinsViewDB::GetMWEBCoin(const mw::Hash& output_id, Output& coin) const {
+    UTXO::CPtr pUTXO = GetMWEBView()->GetUTXO(output_id);
+    if (pUTXO != nullptr) {
+        coin = pUTXO->GetOutput();
+        return true;
+    }
+
+    return false;
+}
+
 uint256 CCoinsViewDB::GetBestBlock() const {
     uint256 hashBestChain;
     if (!m_db->Read(DB_BEST_BLOCK, hashBestChain))
diff --git a/src/txdb.h b/src/txdb.h
index a267559a9..4e850185e 100644
--- a/src/txdb.h
+++ b/src/txdb.h
@@ -66,6 +66,7 @@ public:
     CDBWrapper* GetDB() noexcept { return m_db.get(); }
     void SetMWEBView(const mw::ICoinsView::Ptr& view) { mweb_view = view; }
     mw::ICoinsView::Ptr GetMWEBView() const final { return mweb_view; }
+    bool GetMWEBCoin(const mw::Hash& output_id, Output& coin) const final;
 
     //! Attempt to update from an older database format. Returns whether an error occurred.
     bool Upgrade();
diff --git a/src/txmempool.cpp b/src/txmempool.cpp
index f9cee41ba..d9c8e3872 100644
--- a/src/txmempool.cpp
+++ b/src/txmempool.cpp
@@ -165,8 +165,8 @@ bool CTxMemPool::CalculateMemPoolAncestors(const CTxMemPoolEntry &entry, setEntr
         // Get parents of this transaction that are in the mempool
         // GetMemPoolParents() is only valid for entries in the mempool, so we
         // iterate mapTx to find parents.
-        for (unsigned int i = 0; i < tx.vin.size(); i++) {
-            Optional<txiter> piter = GetIter(tx.vin[i].prevout.hash);
+        for (const CTxInput& txin : tx.GetInputs()) {
+            Optional<txiter> piter = GetIter(txin);
             if (piter) {
                 staged_ancestors.insert(**piter);
                 if (staged_ancestors.size() + 1 > limitAncestorCount) {
@@ -721,21 +721,22 @@ void CTxMemPool::check(const CCoinsViewCache *pcoins) const
         innerUsage += memusage::DynamicUsage(it->GetMemPoolParentsConst()) + memusage::DynamicUsage(it->GetMemPoolChildrenConst());
         bool fDependsWait = false;
         CTxMemPoolEntry::Parents setParentCheck;
-        for (const CTxIn &txin : tx.vin) {
+        for (const CTxInput& input : tx.GetInputs()) {
             // Check that every mempool transaction's inputs refer to available coins, or other mempool tx's.
-            indexed_transaction_set::const_iterator it2 = mapTx.find(txin.prevout.hash);
-            if (it2 != mapTx.end()) {
-                const CTransaction& tx2 = it2->GetTx();
-                assert(tx2.vout.size() > txin.prevout.n && !tx2.vout[txin.prevout.n].IsNull());
+            auto opt_it2 = GetIter(input);
+            if (opt_it2) {
+                auto it2 = *opt_it2;
+                //const CTransaction& tx2 = it2->GetTx();
+                //assert(tx2.vout.size() > txin.prevout.n && !tx2.vout[txin.prevout.n].IsNull()); // MW: TODO -
                 fDependsWait = true;
                 setParentCheck.insert(*it2);
             } else {
-                assert(pcoins->HaveCoin(txin.prevout));
+                assert(pcoins->HaveCoin(input.GetIndex()));
             }
             // Check whether its inputs are marked in mapNextTx.
-            auto it3 = mapNextTx.find(txin.prevout);
+            auto it3 = mapNextTx.find(input.GetIndex());
             assert(it3 != mapNextTx.end());
-            assert(it3->first == OutputIndex(txin.prevout));
+            assert(it3->first == input.GetIndex());
             assert(it3->second == &tx);
             i++;
         }
@@ -967,6 +968,21 @@ Optional<CTxMemPool::txiter> CTxMemPool::GetIter(const uint256& txid) const
 {
     auto it = mapTx.find(txid);
     if (it != mapTx.end()) return it;
+
+    return Optional<txiter>{};
+}
+
+Optional<CTxMemPool::txiter> CTxMemPool::GetIter(const CTxInput& input) const
+{
+    if (input.IsMWEB()) {
+        auto iter = mapTxOutputs_MWEB.find(input.ToMWEB());
+        if (iter != mapTxOutputs_MWEB.end()) {
+            return GetIter(iter->second->GetHash());
+        }
+    } else {
+        return GetIter(input.GetTxIn().prevout.hash);
+    }
+
     return Optional<txiter>{};
 }
 
@@ -1013,6 +1029,50 @@ bool CCoinsViewMemPool::GetCoin(const COutPoint &outpoint, Coin &coin) const {
     return base->GetCoin(outpoint, coin);
 }
 
+bool CCoinsViewMemPool::HaveCoin(const OutputIndex& index) const 
+{
+    if (index.type() == typeid(mw::Hash)) {
+        LogPrintf("Checking mempool\n");
+        if (mempool.mapNextTx.find(index) != mempool.mapNextTx.end()) {
+            LogPrintf("Spend found in mempool!\n");
+            return false;
+        }
+
+        auto iter = mempool.mapTxOutputs_MWEB.find(boost::get<mw::Hash>(index));
+        if (iter != mempool.mapTxOutputs_MWEB.end()) {
+            LogPrintf("Coin in mempool!\n");
+            assert(mempool.mapTx.count(iter->second->GetHash()) > 0);
+            return true;
+        }
+
+        return GetMWEBView()->HasCoin(boost::get<mw::Hash>(index));
+    } else {
+        return base->HaveCoin(index);
+    }
+}
+
+bool CCoinsViewMemPool::GetMWEBCoin(const mw::Hash& output_id, Output& coin) const
+{
+    if (mempool.mapNextTx.find(output_id) != mempool.mapNextTx.end()) {
+        return false;
+    }
+
+    auto iter = mempool.mapTxOutputs_MWEB.find(output_id);
+    if (iter != mempool.mapTxOutputs_MWEB.end()) {
+        //assert(mempool.mapTx.count(iter->second->GetHash()) > 0);
+        //assert(!iter->second->mweb_tx.IsNull());
+        return iter->second->mweb_tx.GetOutput(output_id, coin);
+    }
+
+    UTXO::CPtr pUTXO = GetMWEBView()->GetUTXO(output_id);
+    if (pUTXO) {
+        coin = pUTXO->GetOutput();
+        return true;
+    }
+
+    return false;
+}
+
 size_t CTxMemPool::DynamicMemoryUsage() const {
     LOCK(cs);
     // Estimate the overhead of mapTx to be 15 pointers + an allocation, as no exact formula for boost::multi_index_contained is implemented.
diff --git a/src/txmempool.h b/src/txmempool.h
index 0c9cac126..8cddf3f25 100644
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -683,6 +683,9 @@ public:
     /** Returns an iterator to the given hash, if found */
     Optional<txiter> GetIter(const uint256& txid) const EXCLUSIVE_LOCKS_REQUIRED(cs);
 
+    /** Returns an iterator to the transaction the input spends from, if found */
+    Optional<txiter> GetIter(const CTxInput& input) const EXCLUSIVE_LOCKS_REQUIRED(cs);
+
     /** Translate a set of hashes into a set of pool iterators to avoid repeated lookups */
     setEntries GetIterSet(const std::set<uint256>& hashes) const EXCLUSIVE_LOCKS_REQUIRED(cs);
 
@@ -940,6 +943,8 @@ protected:
 public:
     CCoinsViewMemPool(CCoinsView* baseIn, const CTxMemPool& mempoolIn);
     bool GetCoin(const COutPoint &outpoint, Coin &coin) const override;
+    bool HaveCoin(const OutputIndex& index) const override;
+    bool GetMWEBCoin(const mw::Hash& output_id, Output& coin) const override;
 };
 
 /**
diff --git a/src/validation.cpp b/src/validation.cpp
index 365feae4c..6932df4d1 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -1504,6 +1504,10 @@ void UpdateCoins(const CTransaction& tx, CCoinsViewCache& inputs, CTxUndo &txund
     }
     // add outputs
     AddCoins(inputs, tx, nHeight);
+
+    if (!tx.mweb_tx.IsNull()) {
+        inputs.GetMWEBCacheView()->AddTx(tx.mweb_tx.m_transaction);
+    }
 }
 
 void UpdateCoins(const CTransaction& tx, CCoinsViewCache& inputs, int nHeight)
diff --git a/test/functional/mweb_wallet_basic.py b/test/functional/mweb_wallet_basic.py
index cd3e67999..9a1cee7cf 100644
--- a/test/functional/mweb_wallet_basic.py
+++ b/test/functional/mweb_wallet_basic.py
@@ -100,8 +100,11 @@ class MWEBWalletBasicTest(BitcoinTestFramework):
         assert tx3_id in node1.getrawmempool()
 
         self.log.info("Mine next block so node2 sees the transactions")
-        node0.generate(1)
+        node0.generate(2)
         self.sync_all()
+        
+        assert tx2_id not in node1.getrawmempool()
+        assert tx3_id not in node1.getrawmempool()
 
         self.log.info("Verify node2's wallet receives the first pegout transaction")
         n2_addr_coins = node2.listreceivedbyaddress(minconf=0, address_filter=n2_addr)
@@ -113,7 +116,7 @@ class MWEBWalletBasicTest(BitcoinTestFramework):
         n2_addr2_coins = node2.listreceivedbyaddress(minconf=0)
         self.log.info(n2_addr2_coins)
         assert_equal(len(n2_addr2_coins), 1)
-        assert n2_addr2_coins['amount'] < 5 and n2_addr2_coins['amount'] > 4.9
+        assert n2_addr2_coins[0]['amount'] < 5 and n2_addr2_coins[0]['amount'] > 4.9
         assert_equal(n2_addr2_coins[0]['confirmations'], 1)
         
         n2_balances = node2.getbalances()['mine']