diff --git a/src/addrman.cpp b/src/addrman.cpp
index a56bb4f9c1c..7f494ded12a 100644
--- a/src/addrman.cpp
+++ b/src/addrman.cpp
@@ -390,9 +390,9 @@ int CAddrMan::Check_()
     if (vRandom.size() != nTried + nNew)
         return -7;
 
-    for (std::map<int, CAddrInfo>::iterator it = mapInfo.begin(); it != mapInfo.end(); it++) {
-        int n = (*it).first;
-        CAddrInfo& info = (*it).second;
+    for (const auto& entry : mapInfo) {
+        int n = entry.first;
+        const CAddrInfo& info = entry.second;
         if (info.fInTried) {
             if (!info.nLastSuccess)
                 return -1;
diff --git a/src/addrman.h b/src/addrman.h
index 18f30622873..e58fb4a3695 100644
--- a/src/addrman.h
+++ b/src/addrman.h
@@ -313,9 +313,9 @@ public:
         s << nUBuckets;
         std::map<int, int> mapUnkIds;
         int nIds = 0;
-        for (std::map<int, CAddrInfo>::const_iterator it = mapInfo.begin(); it != mapInfo.end(); it++) {
-            mapUnkIds[(*it).first] = nIds;
-            const CAddrInfo &info = (*it).second;
+        for (const auto& entry : mapInfo) {
+            mapUnkIds[entry.first] = nIds;
+            const CAddrInfo &info = entry.second;
             if (info.nRefCount) {
                 assert(nIds != nNew); // this means nNew was wrong, oh ow
                 s << info;
@@ -323,8 +323,8 @@ public:
             }
         }
         nIds = 0;
-        for (std::map<int, CAddrInfo>::const_iterator it = mapInfo.begin(); it != mapInfo.end(); it++) {
-            const CAddrInfo &info = (*it).second;
+        for (const auto& entry : mapInfo) {
+            const CAddrInfo &info = entry.second;
             if (info.fInTried) {
                 assert(nIds != nTried); // this means nTried was wrong, oh ow
                 s << info;
diff --git a/src/net.cpp b/src/net.cpp
index ea3840a7086..0768fd958cd 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -110,13 +110,13 @@ bool GetLocal(CService& addr, const CNetAddr *paddrPeer)
     int nBestReachability = -1;
     {
         LOCK(cs_mapLocalHost);
-        for (std::map<CNetAddr, LocalServiceInfo>::iterator it = mapLocalHost.begin(); it != mapLocalHost.end(); it++)
+        for (const auto& entry : mapLocalHost)
         {
-            int nScore = (*it).second.nScore;
-            int nReachability = (*it).first.GetReachabilityFrom(paddrPeer);
+            int nScore = entry.second.nScore;
+            int nReachability = entry.first.GetReachabilityFrom(paddrPeer);
             if (nReachability > nBestReachability || (nReachability == nBestReachability && nScore > nBestScore))
             {
-                addr = CService((*it).first, (*it).second.nPort);
+                addr = CService(entry.first, entry.second.nPort);
                 nBestReachability = nReachability;
                 nBestScore = nScore;
             }
diff --git a/src/qt/bantablemodel.cpp b/src/qt/bantablemodel.cpp
index f8a99506c13..90e1eed9a26 100644
--- a/src/qt/bantablemodel.cpp
+++ b/src/qt/bantablemodel.cpp
@@ -55,11 +55,11 @@ public:
 #if QT_VERSION >= 0x040700
         cachedBanlist.reserve(banMap.size());
 #endif
-        for (banmap_t::iterator it = banMap.begin(); it != banMap.end(); it++)
+        for (const auto& entry : banMap)
         {
             CCombinedBan banEntry;
-            banEntry.subnet = (*it).first;
-            banEntry.banEntry = (*it).second;
+            banEntry.subnet = entry.first;
+            banEntry.banEntry = entry.second;
             cachedBanlist.append(banEntry);
         }
 
diff --git a/src/qt/transactiontablemodel.cpp b/src/qt/transactiontablemodel.cpp
index 59cef555b1a..ff75ab89b9e 100644
--- a/src/qt/transactiontablemodel.cpp
+++ b/src/qt/transactiontablemodel.cpp
@@ -80,10 +80,10 @@ public:
         cachedWallet.clear();
         {
             LOCK2(cs_main, wallet->cs_wallet);
-            for(std::map<uint256, CWalletTx>::iterator it = wallet->mapWallet.begin(); it != wallet->mapWallet.end(); ++it)
+            for (const auto& entry : wallet->mapWallet)
             {
-                if(TransactionRecord::showTransaction(it->second))
-                    cachedWallet.append(TransactionRecord::decomposeTransaction(wallet, it->second));
+                if (TransactionRecord::showTransaction(entry.second))
+                    cachedWallet.append(TransactionRecord::decomposeTransaction(wallet, entry.second));
             }
         }
     }
diff --git a/src/rpc/net.cpp b/src/rpc/net.cpp
index a3d3df26a3b..86beba30d53 100644
--- a/src/rpc/net.cpp
+++ b/src/rpc/net.cpp
@@ -569,11 +569,11 @@ UniValue listbanned(const JSONRPCRequest& request)
     g_connman->GetBanned(banMap);
 
     UniValue bannedAddresses(UniValue::VARR);
-    for (banmap_t::iterator it = banMap.begin(); it != banMap.end(); it++)
+    for (const auto& entry : banMap)
     {
-        CBanEntry banEntry = (*it).second;
+        const CBanEntry& banEntry = entry.second;
         UniValue rec(UniValue::VOBJ);
-        rec.push_back(Pair("address", (*it).first.ToString()));
+        rec.push_back(Pair("address", entry.first.ToString()));
         rec.push_back(Pair("banned_until", banEntry.nBanUntil));
         rec.push_back(Pair("ban_created", banEntry.nCreateTime));
         rec.push_back(Pair("ban_reason", banEntry.banReasonToString()));
diff --git a/src/rpc/server.cpp b/src/rpc/server.cpp
index a73b697e01e..53e90b93fde 100644
--- a/src/rpc/server.cpp
+++ b/src/rpc/server.cpp
@@ -160,8 +160,8 @@ std::string CRPCTable::help(const std::string& strCommand, const JSONRPCRequest&
     std::set<rpcfn_type> setDone;
     std::vector<std::pair<std::string, const CRPCCommand*> > vCommands;
 
-    for (std::map<std::string, const CRPCCommand*>::const_iterator mi = mapCommands.begin(); mi != mapCommands.end(); ++mi)
-        vCommands.push_back(make_pair(mi->second->category + mi->first, mi->second));
+    for (const auto& entry : mapCommands)
+        vCommands.push_back(make_pair(entry.second->category + entry.first, entry.second));
     sort(vCommands.begin(), vCommands.end());
 
     JSONRPCRequest jreq(helpreq);
diff --git a/src/serialize.h b/src/serialize.h
index eeb05fa76c8..bb755c9b3df 100644
--- a/src/serialize.h
+++ b/src/serialize.h
@@ -732,8 +732,8 @@ template<typename Stream, typename K, typename T, typename Pred, typename A>
 void Serialize(Stream& os, const std::map<K, T, Pred, A>& m)
 {
     WriteCompactSize(os, m.size());
-    for (typename std::map<K, T, Pred, A>::const_iterator mi = m.begin(); mi != m.end(); ++mi)
-        Serialize(os, (*mi));
+    for (const auto& entry : m)
+        Serialize(os, entry);
 }
 
 template<typename Stream, typename K, typename T, typename Pred, typename A>
diff --git a/src/test/coins_tests.cpp b/src/test/coins_tests.cpp
index dc358bff95c..067eee9dbd3 100644
--- a/src/test/coins_tests.cpp
+++ b/src/test/coins_tests.cpp
@@ -81,8 +81,8 @@ public:
         // Manually recompute the dynamic usage of the whole data, and compare it.
         size_t ret = memusage::DynamicUsage(cacheCoins);
         size_t count = 0;
-        for (CCoinsMap::iterator it = cacheCoins.begin(); it != cacheCoins.end(); it++) {
-            ret += it->second.coin.DynamicMemoryUsage();
+        for (const auto& entry : cacheCoins) {
+            ret += entry.second.coin.DynamicMemoryUsage();
             ++count;
         }
         BOOST_CHECK_EQUAL(GetCacheSize(), count);
@@ -189,15 +189,15 @@ BOOST_AUTO_TEST_CASE(coins_cache_simulation_test)
 
         // Once every 1000 iterations and at the end, verify the full cache.
         if (InsecureRandRange(1000) == 1 || i == NUM_SIMULATION_ITERATIONS - 1) {
-            for (auto it = result.begin(); it != result.end(); it++) {
-                bool have = stack.back()->HaveCoin(it->first);
-                const Coin& coin = stack.back()->AccessCoin(it->first);
+            for (const auto& entry : result) {
+                bool have = stack.back()->HaveCoin(entry.first);
+                const Coin& coin = stack.back()->AccessCoin(entry.first);
                 BOOST_CHECK(have == !coin.IsSpent());
-                BOOST_CHECK(coin == it->second);
+                BOOST_CHECK(coin == entry.second);
                 if (coin.IsSpent()) {
                     missed_an_entry = true;
                 } else {
-                    BOOST_CHECK(stack.back()->HaveCoinInCache(it->first));
+                    BOOST_CHECK(stack.back()->HaveCoinInCache(entry.first));
                     found_an_entry = true;
                 }
             }
@@ -420,11 +420,11 @@ BOOST_AUTO_TEST_CASE(updatecoins_simulation_test)
 
         // Once every 1000 iterations and at the end, verify the full cache.
         if (InsecureRandRange(1000) == 1 || i == NUM_SIMULATION_ITERATIONS - 1) {
-            for (auto it = result.begin(); it != result.end(); it++) {
-                bool have = stack.back()->HaveCoin(it->first);
-                const Coin& coin = stack.back()->AccessCoin(it->first);
+            for (const auto& entry : result) {
+                bool have = stack.back()->HaveCoin(entry.first);
+                const Coin& coin = stack.back()->AccessCoin(entry.first);
                 BOOST_CHECK(have == !coin.IsSpent());
-                BOOST_CHECK(coin == it->second);
+                BOOST_CHECK(coin == entry.second);
             }
         }
 
diff --git a/src/validation.cpp b/src/validation.cpp
index e098de5d3da..be9cc6f2309 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -3249,8 +3249,8 @@ void PruneOneBlockFile(const int fileNumber)
 {
     LOCK(cs_LastBlockFile);
 
-    for (BlockMap::iterator it = mapBlockIndex.begin(); it != mapBlockIndex.end(); ++it) {
-        CBlockIndex* pindex = it->second;
+    for (const auto& entry : mapBlockIndex) {
+        CBlockIndex* pindex = entry.second;
         if (pindex->nFile == fileNumber) {
             pindex->nStatus &= ~BLOCK_HAVE_DATA;
             pindex->nStatus &= ~BLOCK_HAVE_UNDO;
@@ -3802,8 +3802,8 @@ bool RewindBlockIndex(const CChainParams& params)
     // Reduce validity flag and have-data flags.
     // We do this after actual disconnecting, otherwise we'll end up writing the lack of data
     // to disk before writing the chainstate, resulting in a failure to continue if interrupted.
-    for (BlockMap::iterator it = mapBlockIndex.begin(); it != mapBlockIndex.end(); it++) {
-        CBlockIndex* pindexIter = it->second;
+    for (const auto& entry : mapBlockIndex) {
+        CBlockIndex* pindexIter = entry.second;
 
         // Note: If we encounter an insufficiently validated block that
         // is on chainActive, it must be because we are a pruning node, and
@@ -4078,8 +4078,8 @@ void static CheckBlockIndex(const Consensus::Params& consensusParams)
 
     // Build forward-pointing map of the entire block tree.
     std::multimap<CBlockIndex*,CBlockIndex*> forward;
-    for (BlockMap::iterator it = mapBlockIndex.begin(); it != mapBlockIndex.end(); it++) {
-        forward.insert(std::make_pair(it->second->pprev, it->second));
+    for (auto& entry : mapBlockIndex) {
+        forward.insert(std::make_pair(entry.second->pprev, entry.second));
     }
 
     assert(forward.size() == mapBlockIndex.size());
diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index 5d98498a4b0..dd494128308 100644
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -1398,14 +1398,14 @@ UniValue ListReceived(CWallet * const pwallet, const UniValue& params, bool fByA
 
     if (fByAccounts)
     {
-        for (std::map<std::string, tallyitem>::iterator it = mapAccountTally.begin(); it != mapAccountTally.end(); ++it)
+        for (const auto& entry : mapAccountTally)
         {
-            CAmount nAmount = (*it).second.nAmount;
-            int nConf = (*it).second.nConf;
+            CAmount nAmount = entry.second.nAmount;
+            int nConf = entry.second.nConf;
             UniValue obj(UniValue::VOBJ);
-            if((*it).second.fIsWatchonly)
+            if (entry.second.fIsWatchonly)
                 obj.push_back(Pair("involvesWatchonly", true));
-            obj.push_back(Pair("account",       (*it).first));
+            obj.push_back(Pair("account",       entry.first));
             obj.push_back(Pair("amount",        ValueFromAmount(nAmount)));
             obj.push_back(Pair("confirmations", (nConf == std::numeric_limits<int>::max() ? 0 : nConf)));
             ret.push_back(obj);
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 925b474d73c..e94f5c2c00d 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -701,9 +701,9 @@ DBErrors CWallet::ReorderTransactions()
     typedef std::multimap<int64_t, TxPair > TxItems;
     TxItems txByTime;
 
-    for (std::map<uint256, CWalletTx>::iterator it = mapWallet.begin(); it != mapWallet.end(); ++it)
+    for (auto& entry : mapWallet)
     {
-        CWalletTx* wtx = &((*it).second);
+        CWalletTx* wtx = &entry.second;
         txByTime.insert(std::make_pair(wtx->nTimeReceived, TxPair(wtx, nullptr)));
     }
     std::list<CAccountingEntry> acentries;
@@ -1966,9 +1966,9 @@ CAmount CWallet::GetBalance() const
     CAmount nTotal = 0;
     {
         LOCK2(cs_main, cs_wallet);
-        for (std::map<uint256, CWalletTx>::const_iterator it = mapWallet.begin(); it != mapWallet.end(); ++it)
+        for (const auto& entry : mapWallet)
         {
-            const CWalletTx* pcoin = &(*it).second;
+            const CWalletTx* pcoin = &entry.second;
             if (pcoin->IsTrusted())
                 nTotal += pcoin->GetAvailableCredit();
         }
@@ -1982,9 +1982,9 @@ CAmount CWallet::GetUnconfirmedBalance() const
     CAmount nTotal = 0;
     {
         LOCK2(cs_main, cs_wallet);
-        for (std::map<uint256, CWalletTx>::const_iterator it = mapWallet.begin(); it != mapWallet.end(); ++it)
+        for (const auto& entry : mapWallet)
         {
-            const CWalletTx* pcoin = &(*it).second;
+            const CWalletTx* pcoin = &entry.second;
             if (!pcoin->IsTrusted() && pcoin->GetDepthInMainChain() == 0 && pcoin->InMempool())
                 nTotal += pcoin->GetAvailableCredit();
         }
@@ -1997,9 +1997,9 @@ CAmount CWallet::GetImmatureBalance() const
     CAmount nTotal = 0;
     {
         LOCK2(cs_main, cs_wallet);
-        for (std::map<uint256, CWalletTx>::const_iterator it = mapWallet.begin(); it != mapWallet.end(); ++it)
+        for (const auto& entry : mapWallet)
         {
-            const CWalletTx* pcoin = &(*it).second;
+            const CWalletTx* pcoin = &entry.second;
             nTotal += pcoin->GetImmatureCredit();
         }
     }
@@ -2011,9 +2011,9 @@ CAmount CWallet::GetWatchOnlyBalance() const
     CAmount nTotal = 0;
     {
         LOCK2(cs_main, cs_wallet);
-        for (std::map<uint256, CWalletTx>::const_iterator it = mapWallet.begin(); it != mapWallet.end(); ++it)
+        for (const auto& entry : mapWallet)
         {
-            const CWalletTx* pcoin = &(*it).second;
+            const CWalletTx* pcoin = &entry.second;
             if (pcoin->IsTrusted())
                 nTotal += pcoin->GetAvailableWatchOnlyCredit();
         }
@@ -2027,9 +2027,9 @@ CAmount CWallet::GetUnconfirmedWatchOnlyBalance() const
     CAmount nTotal = 0;
     {
         LOCK2(cs_main, cs_wallet);
-        for (std::map<uint256, CWalletTx>::const_iterator it = mapWallet.begin(); it != mapWallet.end(); ++it)
+        for (const auto& entry : mapWallet)
         {
-            const CWalletTx* pcoin = &(*it).second;
+            const CWalletTx* pcoin = &entry.second;
             if (!pcoin->IsTrusted() && pcoin->GetDepthInMainChain() == 0 && pcoin->InMempool())
                 nTotal += pcoin->GetAvailableWatchOnlyCredit();
         }
@@ -2042,9 +2042,9 @@ CAmount CWallet::GetImmatureWatchOnlyBalance() const
     CAmount nTotal = 0;
     {
         LOCK2(cs_main, cs_wallet);
-        for (std::map<uint256, CWalletTx>::const_iterator it = mapWallet.begin(); it != mapWallet.end(); ++it)
+        for (const auto& entry : mapWallet)
         {
-            const CWalletTx* pcoin = &(*it).second;
+            const CWalletTx* pcoin = &entry.second;
             nTotal += pcoin->GetImmatureWatchOnlyCredit();
         }
     }
@@ -2118,10 +2118,10 @@ void CWallet::AvailableCoins(std::vector<COutput> &vCoins, bool fOnlySafe, const
 
         CAmount nTotal = 0;
 
-        for (std::map<uint256, CWalletTx>::const_iterator it = mapWallet.begin(); it != mapWallet.end(); ++it)
+        for (const auto& entry : mapWallet)
         {
-            const uint256& wtxid = it->first;
-            const CWalletTx* pcoin = &(*it).second;
+            const uint256& wtxid = entry.first;
+            const CWalletTx* pcoin = &entry.second;
 
             if (!CheckFinalTx(*pcoin))
                 continue;
@@ -2182,10 +2182,10 @@ void CWallet::AvailableCoins(std::vector<COutput> &vCoins, bool fOnlySafe, const
                 if (pcoin->tx->vout[i].nValue < nMinimumAmount || pcoin->tx->vout[i].nValue > nMaximumAmount)
                     continue;
 
-                if (coinControl && coinControl->HasSelected() && !coinControl->fAllowOtherInputs && !coinControl->IsSelected(COutPoint((*it).first, i)))
+                if (coinControl && coinControl->HasSelected() && !coinControl->fAllowOtherInputs && !coinControl->IsSelected(COutPoint(entry.first, i)))
                     continue;
 
-                if (IsLockedCoin((*it).first, i))
+                if (IsLockedCoin(entry.first, i))
                     continue;
 
                 if (IsSpent(wtxid, i))
@@ -3640,9 +3640,9 @@ void CWallet::GetKeyBirthTimes(std::map<CTxDestination, int64_t> &mapKeyBirth) c
 
     // find first block that affects those keys, if there are any left
     std::vector<CKeyID> vAffected;
-    for (std::map<uint256, CWalletTx>::const_iterator it = mapWallet.begin(); it != mapWallet.end(); it++) {
+    for (const auto& entry : mapWallet) {
         // iterate over all wallet transactions...
-        const CWalletTx &wtx = (*it).second;
+        const CWalletTx &wtx = entry.second;
         BlockMap::const_iterator blit = mapBlockIndex.find(wtx.hashBlock);
         if (blit != mapBlockIndex.end() && chainActive.Contains(blit->second)) {
             // ... which are already in a block
@@ -3662,8 +3662,8 @@ void CWallet::GetKeyBirthTimes(std::map<CTxDestination, int64_t> &mapKeyBirth) c
     }
 
     // Extract block timestamps for those keys
-    for (std::map<CKeyID, CBlockIndex*>::const_iterator it = mapKeyFirstBlock.begin(); it != mapKeyFirstBlock.end(); it++)
-        mapKeyBirth[it->first] = it->second->GetBlockTime() - TIMESTAMP_WINDOW; // block times can be 2h off
+    for (const auto& entry : mapKeyFirstBlock)
+        mapKeyBirth[entry.first] = entry.second->GetBlockTime() - TIMESTAMP_WINDOW; // block times can be 2h off
 }
 
 /**
diff --git a/src/zmq/zmqnotificationinterface.cpp b/src/zmq/zmqnotificationinterface.cpp
index 9909395d845..23669688624 100644
--- a/src/zmq/zmqnotificationinterface.cpp
+++ b/src/zmq/zmqnotificationinterface.cpp
@@ -40,15 +40,15 @@ CZMQNotificationInterface* CZMQNotificationInterface::Create()
     factories["pubrawblock"] = CZMQAbstractNotifier::Create<CZMQPublishRawBlockNotifier>;
     factories["pubrawtx"] = CZMQAbstractNotifier::Create<CZMQPublishRawTransactionNotifier>;
 
-    for (std::map<std::string, CZMQNotifierFactory>::const_iterator i=factories.begin(); i!=factories.end(); ++i)
+    for (const auto& entry : factories)
     {
-        std::string arg("-zmq" + i->first);
+        std::string arg("-zmq" + entry.first);
         if (gArgs.IsArgSet(arg))
         {
-            CZMQNotifierFactory factory = i->second;
+            CZMQNotifierFactory factory = entry.second;
             std::string address = gArgs.GetArg(arg, "");
             CZMQAbstractNotifier *notifier = factory();
-            notifier->SetType(i->first);
+            notifier->SetType(entry.first);
             notifier->SetAddress(address);
             notifiers.push_back(notifier);
         }