diff --git a/src/httprpc.cpp b/src/httprpc.cpp
index 32119c8c7..29121d48f 100644
--- a/src/httprpc.cpp
+++ b/src/httprpc.cpp
@@ -31,7 +31,7 @@ static const char* WWW_AUTH_HEADER_DATA = "Basic realm=\"jsonrpc\"";
 class HTTPRPCTimer : public RPCTimerBase
 {
 public:
-    HTTPRPCTimer(struct event_base* eventBase, std::function<void(void)>& func, int64_t millis) :
+    HTTPRPCTimer(struct event_base* eventBase, std::function<void()>& func, int64_t millis) :
         ev(eventBase, false, func)
     {
         struct timeval tv;
@@ -53,7 +53,7 @@ class HTTPRPCTimerInterface : public RPCTimerInterface
     {
         return "HTTP";
     }
-    RPCTimerBase* NewTimer(std::function<void(void)>& func, int64_t millis) override
+    RPCTimerBase* NewTimer(std::function<void()>& func, int64_t millis) override
     {
         return new HTTPRPCTimer(base, func, millis);
     }
diff --git a/src/qt/rpcconsole.cpp b/src/qt/rpcconsole.cpp
index 825ca541e..bf9dd81eb 100644
--- a/src/qt/rpcconsole.cpp
+++ b/src/qt/rpcconsole.cpp
@@ -106,7 +106,7 @@ class QtRPCTimerBase: public QObject, public RPCTimerBase
 {
     Q_OBJECT
 public:
-    QtRPCTimerBase(std::function<void(void)>& _func, int64_t millis):
+    QtRPCTimerBase(std::function<void()>& _func, int64_t millis):
         func(_func)
     {
         timer.setSingleShot(true);
@@ -118,7 +118,7 @@ private Q_SLOTS:
     void timeout() { func(); }
 private:
     QTimer timer;
-    std::function<void(void)> func;
+    std::function<void()> func;
 };
 
 class QtRPCTimerInterface: public RPCTimerInterface
@@ -126,7 +126,7 @@ class QtRPCTimerInterface: public RPCTimerInterface
 public:
     ~QtRPCTimerInterface() {}
     const char *Name() { return "Qt"; }
-    RPCTimerBase* NewTimer(std::function<void(void)>& func, int64_t millis)
+    RPCTimerBase* NewTimer(std::function<void()>& func, int64_t millis)
     {
         return new QtRPCTimerBase(func, millis);
     }
diff --git a/src/qt/verge.cpp b/src/qt/verge.cpp
index 52b64e858..4e6e9e3d9 100644
--- a/src/qt/verge.cpp
+++ b/src/qt/verge.cpp
@@ -599,7 +599,7 @@ int main(int argc, char *argv[])
     //   Need to pass name here as CAmount is a typedef (see http://qt-project.org/doc/qt-5/qmetatype.html#qRegisterMetaType)
     //   IMPORTANT if it is no longer a typedef use the normal variant above
     qRegisterMetaType< CAmount >("CAmount");
-    qRegisterMetaType< std::function<void(void)> >("std::function<void(void)>");
+    qRegisterMetaType< std::function<void()> >("std::function<void()>");
 #ifdef ENABLE_WALLET
     qRegisterMetaType<WalletModel*>("WalletModel*");
 #endif
diff --git a/src/rest.cpp b/src/rest.cpp
index b6e3de8d5..8f45db670 100644
--- a/src/rest.cpp
+++ b/src/rest.cpp
@@ -144,11 +144,13 @@ static bool rest_headers(HTTPRequest* req,
     uint256 hash;
     if (!ParseHashStr(hashStr, hash))
         return RESTERR(req, HTTP_BAD_REQUEST, "Invalid hash: " + hashStr);
-
+	
+	const CBlockIndex* tip = nullptr;
     std::vector<const CBlockIndex *> headers;
     headers.reserve(count);
     {
         LOCK(cs_main);
+		tip = chainActive.Tip();
         const CBlockIndex* pindex = LookupBlockIndex(hash);
         while (pindex != nullptr && chainActive.Contains(pindex)) {
             headers.push_back(pindex);
@@ -179,11 +181,8 @@ static bool rest_headers(HTTPRequest* req,
     }
     case RetFormat::JSON: {
         UniValue jsonHeaders(UniValue::VARR);
-        {
-            LOCK(cs_main);
-            for (const CBlockIndex *pindex : headers) {
-                jsonHeaders.push_back(blockheaderToJSON(pindex));
-            }
+        for (const CBlockIndex *pindex : headers) {
+            jsonHeaders.push_back(blockheaderToJSON(tip, pindex));
         }
         std::string strJSON = jsonHeaders.write() + "\n";
         req->WriteHeader("Content-Type", "application/json");
@@ -211,8 +210,10 @@ static bool rest_block(HTTPRequest* req,
 
     CBlock block;
     CBlockIndex* pblockindex = nullptr;
+	CBlockIndex* tip = nullptr;
     {
         LOCK(cs_main);
+		tip = chainActive.Tip();
         pblockindex = LookupBlockIndex(hash);
         if (!pblockindex) {
             return RESTERR(req, HTTP_NOT_FOUND, hashStr + " not found");
@@ -244,11 +245,7 @@ static bool rest_block(HTTPRequest* req,
     }
 
     case RetFormat::JSON: {
-        UniValue objBlock;
-        {
-            LOCK(cs_main);
-            objBlock = blockToJSON(block, pblockindex, showTxDetails);
-        }
+        UniValue objBlock = blockToJSON(block, tip, pblockindex, showTxDetails);
         std::string strJSON = objBlock.write() + "\n";
         req->WriteHeader("Content-Type", "application/json");
         req->WriteReply(HTTP_OK, strJSON);
diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index 3acadbdc8..4edcf8b2c 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -89,15 +89,22 @@ double GetDifficulty(const CBlockIndex* blockindex)
     return dDiff;
 }
 
-UniValue blockheaderToJSON(const CBlockIndex* blockindex)
+static int ComputeNextBlockAndDepth(const CBlockIndex* tip, const CBlockIndex* blockindex, const CBlockIndex*& next)
+{
+    next = tip->GetAncestor(blockindex->nHeight + 1);
+    if (next && next->pprev == blockindex) {
+        return tip->nHeight - blockindex->nHeight + 1;
+    }
+    next = nullptr;
+    return blockindex == tip ? 1 : -1;
+}
+
+UniValue blockheaderToJSON(const CBlockIndex* tip, const CBlockIndex* blockindex)
 {
-    AssertLockHeld(cs_main);
     UniValue result(UniValue::VOBJ);
     result.pushKV("hash", blockindex->GetBlockHash().GetHex());
-    int confirmations = -1;
-    // Only report confirmations if the block is on the main chain
-    if (chainActive.Contains(blockindex))
-        confirmations = chainActive.Height() - blockindex->nHeight + 1;
+    const CBlockIndex* pnext;
+    int confirmations = ComputeNextBlockAndDepth(tip, blockindex, pnext);
     result.pushKV("confirmations", confirmations);
     result.pushKV("height", blockindex->nHeight);
     result.pushKV("version", blockindex->nVersion);
@@ -113,23 +120,19 @@ UniValue blockheaderToJSON(const CBlockIndex* blockindex)
 
     if (blockindex->pprev)
         result.pushKV("previousblockhash", blockindex->pprev->GetBlockHash().GetHex());
-    CBlockIndex *pnext = chainActive.Next(blockindex);
     if (pnext)
         result.pushKV("nextblockhash", pnext->GetBlockHash().GetHex());
     return result;
 }
 
-UniValue blockToJSON(const CBlock& block, const CBlockIndex* blockindex, bool txDetails)
+UniValue blockToJSON(const CBlock& block, const CBlockIndex* tip, const CBlockIndex* blockindex, bool txDetails)
 {
-    AssertLockHeld(cs_main);
     UniValue result(UniValue::VOBJ);
     result.pushKV("hash", blockindex->GetBlockHash().GetHex());
     result.pushKV("pow_hash", block.GetPoWHash(block.GetAlgo()).GetHex());
     result.pushKV("algo", GetAlgoName(block.GetAlgo()));
-    int confirmations = -1;
-    // Only report confirmations if the block is on the main chain
-    if (chainActive.Contains(blockindex))
-        confirmations = chainActive.Height() - blockindex->nHeight + 1;
+    const CBlockIndex* pnext;
+    int confirmations = ComputeNextBlockAndDepth(tip, blockindex, pnext);
     result.pushKV("confirmations", confirmations);
     result.pushKV("strippedsize", (int)::GetSerializeSize(block, SER_NETWORK, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS));
     result.pushKV("size", (int)::GetSerializeSize(block, SER_NETWORK, PROTOCOL_VERSION));
@@ -162,7 +165,6 @@ UniValue blockToJSON(const CBlock& block, const CBlockIndex* blockindex, bool tx
 
     if (blockindex->pprev)
         result.pushKV("previousblockhash", blockindex->pprev->GetBlockHash().GetHex());
-    CBlockIndex *pnext = chainActive.Next(blockindex);
     if (pnext)
         result.pushKV("nextblockhash", pnext->GetBlockHash().GetHex());
     return result;
@@ -746,7 +748,7 @@ static UniValue getblockheader(const JSONRPCRequest& request)
         return strHex;
     }
 
-    return blockheaderToJSON(pblockindex);
+    return blockheaderToJSON(chainActive.Tip(), pblockindex);
 }
 
 static CBlock GetBlockChecked(const CBlockIndex* pblockindex)
@@ -847,7 +849,7 @@ static UniValue getblock(const JSONRPCRequest& request)
         return strHex;
     }
 
-    return blockToJSON(block, pblockindex, verbosity >= 2);
+    return blockToJSON(block, chainActive.Tip(), pblockindex, verbosity >= 2);
 }
 
 static UniValue getrawblockbynumber(const JSONRPCRequest& request)
diff --git a/src/rpc/blockchain.h b/src/rpc/blockchain.h
index 4c9d573a9..001eb4245 100644
--- a/src/rpc/blockchain.h
+++ b/src/rpc/blockchain.h
@@ -25,7 +25,7 @@ double GetDifficulty(int algo);
 void RPCNotifyBlockChange(bool ibd, const CBlockIndex *);
 
 /** Block description to JSON */
-UniValue blockToJSON(const CBlock& block, const CBlockIndex* blockindex, bool txDetails = false);
+UniValue blockToJSON(const CBlock& block, const CBlockIndex* tip, const CBlockIndex* blockindex, bool txDetails = false);
 
 /** Mempool information to JSON */
 UniValue mempoolInfoToJSON();
@@ -34,7 +34,7 @@ UniValue mempoolInfoToJSON();
 UniValue mempoolToJSON(bool fVerbose = false);
 
 /** Block header to JSON */
-UniValue blockheaderToJSON(const CBlockIndex* blockindex);
+UniValue blockheaderToJSON(const CBlockIndex* tip, const CBlockIndex* blockindex);
 
 
 CBlockIndex* GetLastBlockIndex4Algo(CBlockIndex* pindex, int algo);
diff --git a/src/rpc/server.cpp b/src/rpc/server.cpp
index b3c6ebaf7..d164c5d7d 100644
--- a/src/rpc/server.cpp
+++ b/src/rpc/server.cpp
@@ -562,7 +562,7 @@ void RPCUnsetTimerInterface(RPCTimerInterface *iface)
         timerInterface = nullptr;
 }
 
-void RPCRunLater(const std::string& name, std::function<void(void)> func, int64_t nSeconds)
+void RPCRunLater(const std::string& name, std::function<void()> func, int64_t nSeconds)
 {
     if (!timerInterface)
         throw JSONRPCError(RPC_INTERNAL_ERROR, "No timer handler registered for RPC");
diff --git a/src/rpc/server.h b/src/rpc/server.h
index e32d6bba1..0e250af50 100644
--- a/src/rpc/server.h
+++ b/src/rpc/server.h
@@ -111,7 +111,7 @@ class RPCTimerInterface
      * This is needed to cope with the case in which there is no HTTP server, but
      * only GUI RPC console, and to break the dependency of pcserver on httprpc.
      */
-    virtual RPCTimerBase* NewTimer(std::function<void(void)>& func, int64_t millis) = 0;
+    virtual RPCTimerBase* NewTimer(std::function<void()>& func, int64_t millis) = 0;
 };
 
 /** Set the factory function for timers */
@@ -125,7 +125,7 @@ void RPCUnsetTimerInterface(RPCTimerInterface *iface);
  * Run func nSeconds from now.
  * Overrides previous timer <name> (if any).
  */
-void RPCRunLater(const std::string& name, std::function<void(void)> func, int64_t nSeconds);
+void RPCRunLater(const std::string& name, std::function<void()> func, int64_t nSeconds);
 
 typedef UniValue(*rpcfn_type)(const JSONRPCRequest& jsonRequest);
 
diff --git a/src/scheduler.h b/src/scheduler.h
index ffc63be91..482dac3d6 100644
--- a/src/scheduler.h
+++ b/src/scheduler.h
@@ -41,7 +41,7 @@ class CScheduler
     CScheduler();
     ~CScheduler();
 
-    typedef std::function<void(void)> Function;
+    typedef std::function<void()> Function;
 
     // Call func at/after time t
     void schedule(Function f, boost::chrono::system_clock::time_point t=boost::chrono::system_clock::now());