diff --git a/src/Makefile.am b/src/Makefile.am
index 34434b8ab..c639e860b 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -117,6 +117,7 @@ BITCOIN_CORE_H = \
   ecwrapper.h \
   hash.h \
   init.h \
+  json_spirit_wrapper.h \
   key.h \
   keystore.h \
   leveldbwrapper.h \
diff --git a/src/bitcoin-cli.cpp b/src/bitcoin-cli.cpp
index 03a727719..4b4781fbf 100644
--- a/src/bitcoin-cli.cpp
+++ b/src/bitcoin-cli.cpp
@@ -152,7 +152,7 @@ Object CallRPC(const string& strMethod, const Array& params)
         throw runtime_error("no response from server");
 
     // Parse reply
-    Value valReply;
+    Value valReply(UniValue::VSTR);
     if (!valReply.read(strReply))
         throw runtime_error("couldn't parse reply from server");
     const Object& reply = valReply.get_obj();
diff --git a/src/rest.cpp b/src/rest.cpp
index 7c238d506..5f64a0091 100644
--- a/src/rest.cpp
+++ b/src/rest.cpp
@@ -222,7 +222,7 @@ static bool rest_block(AcceptedConnection* conn,
 
     case RF_JSON: {
         Object objBlock = blockToJSON(block, pblockindex, showTxDetails);
-        string strJSON = write_string(Value(objBlock), false) + "\n";
+        string strJSON = objBlock.write() + "\n";
         conn->stream() << HTTPReply(HTTP_OK, strJSON, fRun) << std::flush;
         return true;
     }
@@ -267,8 +267,7 @@ static bool rest_chaininfo(AcceptedConnection* conn,
     case RF_JSON: {
         Array rpcParams;
         Value chainInfoObject = getblockchaininfo(rpcParams, false);
-
-        string strJSON = write_string(chainInfoObject, false) + "\n";
+        string strJSON = chainInfoObject.write() + "\n";
         conn->stream() << HTTPReply(HTTP_OK, strJSON, fRun) << std::flush;
         return true;
     }
@@ -319,7 +318,7 @@ static bool rest_tx(AcceptedConnection* conn,
     case RF_JSON: {
         Object objTx;
         TxToJSON(tx, hashBlock, objTx);
-        string strJSON = write_string(Value(objTx), false) + "\n";
+        string strJSON = objTx.write() + "\n";
         conn->stream() << HTTPReply(HTTP_OK, strJSON, fRun) << std::flush;
         return true;
     }
@@ -516,7 +515,7 @@ static bool rest_getutxos(AcceptedConnection* conn,
         objGetUTXOResponse.push_back(Pair("utxos", utxos));
 
         // return json string
-        string strJSON = write_string(Value(objGetUTXOResponse), false) + "\n";
+        string strJSON = objGetUTXOResponse.write() + "\n";
         conn->stream() << HTTPReply(HTTP_OK, strJSON, fRun) << std::flush;
         return true;
     }
diff --git a/src/rpcblockchain.cpp b/src/rpcblockchain.cpp
index d97b05049..9aa60d44d 100644
--- a/src/rpcblockchain.cpp
+++ b/src/rpcblockchain.cpp
@@ -757,7 +757,7 @@ Value invalidateblock(const Array& params, bool fHelp)
         throw JSONRPCError(RPC_DATABASE_ERROR, state.GetRejectReason());
     }
 
-    return Value::null;
+    return NullUniValue;
 }
 
 Value reconsiderblock(const Array& params, bool fHelp)
@@ -796,5 +796,5 @@ Value reconsiderblock(const Array& params, bool fHelp)
         throw JSONRPCError(RPC_DATABASE_ERROR, state.GetRejectReason());
     }
 
-    return Value::null;
+    return NullUniValue;
 }
diff --git a/src/rpcclient.cpp b/src/rpcclient.cpp
index 60ff66a1e..19b338f66 100644
--- a/src/rpcclient.cpp
+++ b/src/rpcclient.cpp
@@ -138,7 +138,7 @@ static CRPCConvertTable rpcCvtTable;
 /** Convert strings to command-specific RPC representation */
 Array RPCConvertValues(const std::string &strMethod, const std::vector<std::string> &strParams)
 {
-    Array params;
+    UniValue params(UniValue::VARR);
 
     for (unsigned int idx = 0; idx < strParams.size(); idx++) {
         const std::string& strVal = strParams[idx];
diff --git a/src/rpcmining.cpp b/src/rpcmining.cpp
index f8357f773..b112b3cae 100644
--- a/src/rpcmining.cpp
+++ b/src/rpcmining.cpp
@@ -522,7 +522,7 @@ Value getblocktemplate(const Array& params, bool fHelp)
         if (strMode == "proposal")
         {
             const Value& dataval = find_value(oparam, "data");
-            if (dataval.type() != str_type)
+            if (dataval.isStr())
                 throw JSONRPCError(RPC_TYPE_ERROR, "Missing data String key for proposal");
 
             CBlock block;
@@ -646,7 +646,7 @@ Value getblocktemplate(const Array& params, bool fHelp)
     UpdateTime(pblock, Params().GetConsensus(), pindexPrev);
     pblock->nNonce = uint256();
 
-    static const Array aCaps = boost::assign::list_of("proposal");
+    Array aCaps; aCaps.push_back("proposal");
 
     Value txCoinbase = Value::null;
     Array transactions;
diff --git a/src/rpcmisc.cpp b/src/rpcmisc.cpp
index 647643350..5d67b1219 100644
--- a/src/rpcmisc.cpp
+++ b/src/rpcmisc.cpp
@@ -454,8 +454,8 @@ Value setmocktime(const Array& params, bool fHelp)
 
     LOCK(cs_main);
 
-    RPCTypeCheck(params, boost::assign::list_of(int_type));
+    RPCTypeCheck(params, boost::assign::list_of(UniValue::VNUM));
     SetMockTime(params[0].get_int64());
 
-    return Value::null;
+    return NullUniValue;
 }
diff --git a/src/rpcprotocol.cpp b/src/rpcprotocol.cpp
index bdea60410..a095a45b6 100644
--- a/src/rpcprotocol.cpp
+++ b/src/rpcprotocol.cpp
@@ -258,7 +258,7 @@ int ReadHTTPMessage(std::basic_istream<char>& stream, map<string,
 
 string JSONRPCRequest(const string& strMethod, const Array& params, const Value& id)
 {
-    Object request;
+    Object request(UniValue::VOBJ);
     request.push_back(Pair("method", strMethod));
     request.push_back(Pair("params", params));
     request.push_back(Pair("id", id));
@@ -267,7 +267,7 @@ string JSONRPCRequest(const string& strMethod, const Array& params, const Value&
 
 Object JSONRPCReplyObj(const Value& result, const Value& error, const Value& id)
 {
-    Object reply;
+    Object reply(UniValue::VOBJ);
     if (!error.isNull())
         reply.push_back(Pair("result", NullUniValue));
     else
@@ -285,7 +285,7 @@ string JSONRPCReply(const Value& result, const Value& error, const Value& id)
 
 Object JSONRPCError(int code, const string& message)
 {
-    Object error;
+    UniValue error(UniValue::VOBJ);
     error.push_back(Pair("code", code));
     error.push_back(Pair("message", message));
     return error;
diff --git a/src/rpcrawtransaction.cpp b/src/rpcrawtransaction.cpp
index 4c309e994..5367f3d87 100644
--- a/src/rpcrawtransaction.cpp
+++ b/src/rpcrawtransaction.cpp
@@ -306,7 +306,8 @@ Value gettxoutproof(const Array& params, bool fHelp)
     set<uint256> setTxids;
     uint256 oneTxid;
     Array txids = params[0].get_array();
-    BOOST_FOREACH(Value& txid, txids) {
+    for (unsigned int idx = 0; idx < txids.size(); idx++) {
+        const Value& txid = txids[idx];
         if (txid.get_str().length() != 64 || !IsHex(txid.get_str()))
             throw JSONRPCError(RPC_INVALID_PARAMETER, string("Invalid txid ")+txid.get_str());
         uint256 hash(uint256S(txid.get_str()));
@@ -559,7 +560,7 @@ Value decoderawtransaction(const Array& params, bool fHelp)
     if (!DecodeHexTx(tx, params[0].get_str()))
         throw JSONRPCError(RPC_DESERIALIZATION_ERROR, "TX decode failed");
 
-    Object result;
+    UniValue result(UniValue::VOBJ);
     TxToJSON(tx, uint256(), result);
 
     return result;
@@ -591,7 +592,7 @@ Value decodescript(const Array& params, bool fHelp)
         );
 
     LOCK(cs_main);
-    RPCTypeCheck(params, boost::assign::list_of(str_type));
+    RPCTypeCheck(params, boost::assign::list_of(UniValue::VSTR));
 
     Object r;
     CScript script;
diff --git a/src/test/script_tests.cpp b/src/test/script_tests.cpp
index 5bd37111e..fc6b44951 100644
--- a/src/test/script_tests.cpp
+++ b/src/test/script_tests.cpp
@@ -583,11 +583,13 @@ BOOST_AUTO_TEST_CASE(script_build)
         Array json_good = read_json(std::string(json_tests::script_valid, json_tests::script_valid + sizeof(json_tests::script_valid)));
         Array json_bad = read_json(std::string(json_tests::script_invalid, json_tests::script_invalid + sizeof(json_tests::script_invalid)));
 
-        BOOST_FOREACH(Value& tv, json_good) {
-            tests_good.insert(write_string(Value(tv.get_array()), true));
+        for (unsigned int idx = 0; idx < json_good.size(); idx++) {
+            const Value& tv = json_good[idx];
+            tests_good.insert(tv.get_array().write());
         }
-        BOOST_FOREACH(Value& tv, json_bad) {
-            tests_bad.insert(write_string(Value(tv.get_array()), true));
+        for (unsigned int idx = 0; idx < json_bad.size(); idx++) {
+            const Value& tv = json_bad[idx];
+            tests_bad.insert(tv.get_array().write());
         }
     }
 
@@ -596,7 +598,7 @@ BOOST_AUTO_TEST_CASE(script_build)
 
     BOOST_FOREACH(TestBuilder& test, good) {
         test.Test(true);
-        std::string str = write_string(Value(test.GetJSON()), true);
+        std::string str = test.GetJSON().write();
 #ifndef UPDATE_JSON_TESTS
         if (tests_good.count(str) == 0) {
             BOOST_CHECK_MESSAGE(false, "Missing auto script_valid test: " + test.GetComment());
@@ -606,7 +608,7 @@ BOOST_AUTO_TEST_CASE(script_build)
     }
     BOOST_FOREACH(TestBuilder& test, bad) {
         test.Test(false);
-        std::string str = write_string(Value(test.GetJSON()), true);
+        std::string str = test.GetJSON().write();
 #ifndef UPDATE_JSON_TESTS
         if (tests_bad.count(str) == 0) {
             BOOST_CHECK_MESSAGE(false, "Missing auto script_invalid test: " + test.GetComment());
diff --git a/src/test/transaction_tests.cpp b/src/test/transaction_tests.cpp
index 1cadd5745..8e21a98ff 100644
--- a/src/test/transaction_tests.cpp
+++ b/src/test/transaction_tests.cpp
@@ -23,6 +23,7 @@
 
 #include <boost/algorithm/string/classification.hpp>
 #include <boost/algorithm/string/split.hpp>
+#include <boost/assign/list_of.hpp>
 #include <boost/test/unit_test.hpp>
 #include <boost/assign/list_of.hpp>
 
diff --git a/src/wallet/rpcdump.cpp b/src/wallet/rpcdump.cpp
index 2f1564dca..f80c18637 100644
--- a/src/wallet/rpcdump.cpp
+++ b/src/wallet/rpcdump.cpp
@@ -77,7 +77,7 @@ std::string DecodeDumpString(const std::string &str) {
 Value importprivkey(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() < 1 || params.size() > 3)
         throw runtime_error(
@@ -151,7 +151,7 @@ Value importprivkey(const Array& params, bool fHelp)
 Value importaddress(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() < 1 || params.size() > 3)
         throw runtime_error(
@@ -247,7 +247,7 @@ Value z_importwallet(const Array& params, bool fHelp)
 Value importwallet(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() != 1)
         throw runtime_error(
@@ -384,7 +384,7 @@ Value importwallet_impl(const Array& params, bool fHelp, bool fImportZKeys)
 Value dumpprivkey(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() != 1)
         throw runtime_error(
@@ -444,7 +444,7 @@ Value z_exportwallet(const Array& params, bool fHelp)
 Value dumpwallet(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
 
     if (fHelp || params.size() != 1)
         throw runtime_error(
diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index 07fccad36..2defd4b59 100644
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -110,7 +110,7 @@ string AccountFromValue(const Value& value)
 Value getnewaddress(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() > 1)
         throw runtime_error(
@@ -187,7 +187,7 @@ CBitcoinAddress GetAccountAddress(string strAccount, bool bForceNew=false)
 Value getaccountaddress(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() != 1)
         throw runtime_error(
@@ -219,7 +219,7 @@ Value getaccountaddress(const Array& params, bool fHelp)
 Value getrawchangeaddress(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() > 1)
         throw runtime_error(
@@ -254,7 +254,7 @@ Value getrawchangeaddress(const Array& params, bool fHelp)
 Value setaccount(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() < 1 || params.size() > 2)
         throw runtime_error(
@@ -300,7 +300,7 @@ Value setaccount(const Array& params, bool fHelp)
 Value getaccount(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() != 1)
         throw runtime_error(
@@ -332,7 +332,7 @@ Value getaccount(const Array& params, bool fHelp)
 Value getaddressesbyaccount(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() != 1)
         throw runtime_error(
@@ -400,7 +400,7 @@ static void SendMoney(const CTxDestination &address, CAmount nValue, bool fSubtr
 Value sendtoaddress(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() < 2 || params.size() > 5)
         throw runtime_error(
@@ -456,7 +456,7 @@ Value sendtoaddress(const Array& params, bool fHelp)
 Value listaddressgroupings(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp)
         throw runtime_error(
@@ -507,7 +507,7 @@ Value listaddressgroupings(const Array& params, bool fHelp)
 Value signmessage(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() != 2)
         throw runtime_error(
@@ -563,7 +563,7 @@ Value signmessage(const Array& params, bool fHelp)
 Value getreceivedbyaddress(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() < 1 || params.size() > 2)
         throw runtime_error(
@@ -621,7 +621,7 @@ Value getreceivedbyaddress(const Array& params, bool fHelp)
 Value getreceivedbyaccount(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() < 1 || params.size() > 2)
         throw runtime_error(
@@ -710,7 +710,7 @@ CAmount GetAccountBalance(const string& strAccount, int nMinDepth, const isminef
 Value getbalance(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() > 3)
         throw runtime_error(
@@ -782,7 +782,7 @@ Value getbalance(const Array& params, bool fHelp)
 Value getunconfirmedbalance(const Array &params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() > 0)
         throw runtime_error(
@@ -798,7 +798,7 @@ Value getunconfirmedbalance(const Array &params, bool fHelp)
 Value movecmd(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() < 3 || params.size() > 5)
         throw runtime_error(
@@ -868,7 +868,7 @@ Value movecmd(const Array& params, bool fHelp)
 Value sendfrom(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() < 3 || params.size() > 6)
         throw runtime_error(
@@ -931,7 +931,7 @@ Value sendfrom(const Array& params, bool fHelp)
 Value sendmany(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() < 2 || params.size() > 5)
         throw runtime_error(
@@ -1006,9 +1006,11 @@ Value sendmany(const Array& params, bool fHelp)
         totalAmount += nAmount;
 
         bool fSubtractFeeFromAmount = false;
-        BOOST_FOREACH(const Value& addr, subtractFeeFromAmount)
-            if (addr.get_str() == s.name_)
+        for (unsigned int idx = 0; idx < subtractFeeFromAmount.size(); idx++) {
+            const Value& addr = subtractFeeFromAmount[idx];
+            if (addr.get_str() == name_)
                 fSubtractFeeFromAmount = true;
+        }
 
         CRecipient recipient = {scriptPubKey, nAmount, fSubtractFeeFromAmount};
         vecSend.push_back(recipient);
@@ -1041,7 +1043,7 @@ extern CScript _createmultisig_redeemScript(const Array& params);
 Value addmultisigaddress(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() < 2 || params.size() > 3)
     {
@@ -1222,7 +1224,7 @@ Value ListReceived(const Array& params, bool fByAccounts)
 Value listreceivedbyaddress(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() > 3)
         throw runtime_error(
@@ -1259,7 +1261,7 @@ Value listreceivedbyaddress(const Array& params, bool fHelp)
 Value listreceivedbyaccount(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() > 3)
         throw runtime_error(
@@ -1391,7 +1393,7 @@ void AcentryToJSON(const CAccountingEntry& acentry, const string& strAccount, Ar
 Value listtransactions(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() > 4)
         throw runtime_error(
@@ -1512,7 +1514,7 @@ Value listtransactions(const Array& params, bool fHelp)
 Value listaccounts(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() > 2)
         throw runtime_error(
@@ -1592,7 +1594,7 @@ Value listaccounts(const Array& params, bool fHelp)
 Value listsinceblock(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp)
         throw runtime_error(
@@ -1683,7 +1685,7 @@ Value listsinceblock(const Array& params, bool fHelp)
 Value gettransaction(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() < 1 || params.size() > 2)
         throw runtime_error(
@@ -1772,7 +1774,7 @@ Value gettransaction(const Array& params, bool fHelp)
 Value backupwallet(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() != 1)
         throw runtime_error(
@@ -1815,7 +1817,7 @@ Value backupwallet(const Array& params, bool fHelp)
 Value keypoolrefill(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() > 1)
         throw runtime_error(
@@ -1859,7 +1861,7 @@ static void LockWallet(CWallet* pWallet)
 Value walletpassphrase(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (pwalletMain->IsCrypted() && (fHelp || params.size() != 2))
         throw runtime_error(
@@ -1921,7 +1923,7 @@ Value walletpassphrase(const Array& params, bool fHelp)
 Value walletpassphrasechange(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (pwalletMain->IsCrypted() && (fHelp || params.size() != 2))
         throw runtime_error(
@@ -1967,7 +1969,7 @@ Value walletpassphrasechange(const Array& params, bool fHelp)
 Value walletlock(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (pwalletMain->IsCrypted() && (fHelp || params.size() != 0))
         throw runtime_error(
@@ -2006,7 +2008,7 @@ Value walletlock(const Array& params, bool fHelp)
 Value encryptwallet(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
 
     auto fEnableWalletEncryption = fExperimentalMode && GetBoolArg("-developerencryptwallet", false);
 
@@ -2074,7 +2076,7 @@ Value encryptwallet(const Array& params, bool fHelp)
 Value lockunspent(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() < 1 || params.size() > 2)
         throw runtime_error(
@@ -2158,7 +2160,7 @@ Value lockunspent(const Array& params, bool fHelp)
 Value listlockunspent(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() > 0)
         throw runtime_error(
@@ -2207,7 +2209,7 @@ Value listlockunspent(const Array& params, bool fHelp)
 Value settxfee(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() < 1 || params.size() > 1)
         throw runtime_error(
@@ -2236,7 +2238,7 @@ Value settxfee(const Array& params, bool fHelp)
 Value getwalletinfo(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() != 0)
         throw runtime_error(
@@ -2276,7 +2278,7 @@ Value getwalletinfo(const Array& params, bool fHelp)
 Value resendwallettransactions(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() != 0)
         throw runtime_error(
@@ -2301,7 +2303,7 @@ Value resendwallettransactions(const Array& params, bool fHelp)
 Value listunspent(const Array& params, bool fHelp)
 {
     if (!EnsureWalletIsAvailable(fHelp))
-        return Value::null;
+        return NullUniValue;
     
     if (fHelp || params.size() > 3)
         throw runtime_error(
@@ -2339,7 +2341,7 @@ Value listunspent(const Array& params, bool fHelp)
             + HelpExampleRpc("listunspent", "6, 9999999 \"[\\\"1PGFqEzfmQch1gKD3ra4k18PNj3tTUUSqg\\\",\\\"1LtvqCaApEdUGFkpKMM4MstjcaL4dKg8SP\\\"]\"")
         );
 
-    RPCTypeCheck(params, boost::assign::list_of(int_type)(int_type)(array_type));
+    RPCTypeCheck(params, boost::assign::list_of(UniValue::VNUM)(UniValue::VNUM)(UniValue::VARR));
 
     int nMinDepth = 1;
     if (params.size() > 0)
@@ -2352,7 +2354,8 @@ Value listunspent(const Array& params, bool fHelp)
     set<CBitcoinAddress> setAddress;
     if (params.size() > 2) {
         Array inputs = params[2].get_array();
-        BOOST_FOREACH(Value& input, inputs) {
+        for (unsigned int idx = 0; idx < inputs.size(); idx++) {
+            const Value& input = inputs[idx];
             CBitcoinAddress address(input.get_str());
             if (!address.IsValid())
                 throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, string("Invalid Zcash address: ")+input.get_str());