diff --git a/src/main.cpp b/src/main.cpp
index 8306a2c11..5f8737b53 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -3884,22 +3884,27 @@ static bool IsSuperMajority(int minVersion, const CBlockIndex* pstart, unsigned
     return (nFound >= nRequired);
 }
 
-bool static IsCanonicalBlockSignature(const CBlock* pblock)
+bool static IsCanonicalBlockSignature(const CBlock* pblock, bool checkLowS)
 {
     if (pblock->IsProofOfWork()) {
         return pblock->vchBlockSig.empty();
     }
 
-    return IsLowDERSignature(pblock->vchBlockSig, NULL, false);
+    return checkLowS ? IsLowDERSignature(pblock->vchBlockSig, NULL, false) : IsDERSignature(pblock->vchBlockSig, NULL, false);
 }
 
 bool ProcessNewBlock(CValidationState& state, const CChainParams& chainparams, CNode* pfrom, const CBlock* pblock, bool fForceProcessing, const CDiskBlockPos* dbp, bool fMayBanPeerIfInvalid)
 {
-    if (!IsCanonicalBlockSignature(pblock)) {
-            if (pfrom && pfrom->nVersion >= CANONICAL_BLOCK_SIG_VERSION)
-                return state.DoS(100, error("ProcessNewBlock(): bad block signature encoding"),
-                                 REJECT_INVALID, "bad-block-signature-encoding");
-            return false;
+    if (!IsCanonicalBlockSignature(pblock, false)) {
+        if (pfrom && pfrom->nVersion >= CANONICAL_BLOCK_SIG_VERSION)
+            return state.DoS(100, error("ProcessNewBlock(): bad block signature encoding"),
+                            REJECT_INVALID, "bad-block-signature-encoding");
+    }
+
+    if (!IsCanonicalBlockSignature(pblock, true)) {
+        if (pfrom && pfrom->nVersion >= CANONICAL_BLOCK_SIG_LOW_S_VERSION)
+            return state.DoS(100, error("ProcessNewBlock(): bad block signature encoding (low-s)"),
+                            REJECT_INVALID, "bad-block-signature-encoding");
     }
 
     {
diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp
index 8103bce4c..f134f21fb 100644
--- a/src/script/interpreter.cpp
+++ b/src/script/interpreter.cpp
@@ -176,30 +176,19 @@ bool IsLowDERSignature(const valtype &vchSig, ScriptError* serror, bool haveHash
     if (!IsValidSignatureEncoding(vchSig, haveHashType)) {
         return set_error(serror, SCRIPT_ERR_SIG_DER);
     }
-    unsigned int nLenR = vchSig[3];
-    unsigned int nLenS = vchSig[5+nLenR];
-    const unsigned char *S = &vchSig[6+nLenR];
-    // If the S value is above the order of the curve divided by two, its
-    // complement modulo the order could have been used instead, which is
-    // one byte shorter when encoded correctly.
-    if (!CPubKey::CheckSignatureElement(S, nLenS, true))
-        return set_error(serror, SCRIPT_ERR_SIG_HIGH_S);
-
-    return true;
-}
-
-/*
-bool IsLowDERSignature(const valtype &vchSig, ScriptError* serror) {
-    if (!IsValidSignatureEncoding(vchSig)) {
-        return set_error(serror, SCRIPT_ERR_SIG_DER);
-    }
-    std::vector<unsigned char> vchSigCopy(vchSig.begin(), vchSig.begin() + vchSig.size() - 1);
+    std::vector<unsigned char> vchSigCopy(vchSig.begin(), vchSig.begin() + vchSig.size() - (haveHashType ? 1 : 0));
     if (!CPubKey::CheckLowS(vchSigCopy)) {
         return set_error(serror, SCRIPT_ERR_SIG_HIGH_S);
     }
     return true;
 }
-*/
+
+bool IsDERSignature(const valtype &vchSig, ScriptError* serror, bool haveHashType) {
+    if (!IsValidSignatureEncoding(vchSig, haveHashType)) {
+        return set_error(serror, SCRIPT_ERR_SIG_DER);
+    }
+    return true;
+}
 
 bool static IsDefinedHashtypeSignature(const valtype &vchSig) {
     if (vchSig.size() == 0) {
diff --git a/src/script/interpreter.h b/src/script/interpreter.h
index 9753da667..57407cb07 100644
--- a/src/script/interpreter.h
+++ b/src/script/interpreter.h
@@ -162,6 +162,7 @@ public:
 
 bool IsCompressedOrUncompressedPubKey(const std::vector<unsigned char> &vchPubKey);
 bool IsLowDERSignature(const std::vector<unsigned char> &vchSig, ScriptError* serror, bool haveHashType = true);
+bool IsDERSignature(const std::vector<unsigned char> &vchSig, ScriptError* serror, bool haveHashType = true);
 
 bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, unsigned int flags, const BaseSignatureChecker& checker, ScriptError* error = NULL);
 bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, unsigned int flags, const BaseSignatureChecker& checker, ScriptError* error = NULL);
diff --git a/src/version.h b/src/version.h
index b1c661e7e..b3ae38a8b 100644
--- a/src/version.h
+++ b/src/version.h
@@ -17,8 +17,9 @@ static const int INIT_PROTO_VERSION = 209;
 //! In this version, 'getheaders' was introduced.
 static const int GETHEADERS_VERSION = 31800;
 
-//! demand canonical block signatures starting from this version
-static const int CANONICAL_BLOCK_SIG_VERSION = 60018;
+//! reject blocks with non-canonical signatures starting from this version
+static const int CANONICAL_BLOCK_SIG_VERSION = 60016;
+static const int CANONICAL_BLOCK_SIG_LOW_S_VERSION = 60018;
 
 //! disconnect from peers older than this proto version
 static const int MIN_PEER_PROTO_VERSION = CANONICAL_BLOCK_SIG_VERSION;