diff --git a/src/main.cpp b/src/main.cpp
index a19719620..9b45e9433 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -3575,6 +3575,14 @@ bool ContextualCheckBlockHeader(const CBlockHeader& block, CValidationState& sta
         return state.Invalid(error("%s: block timestamp too far in the future", __func__),
                              REJECT_INVALID, "time-too-new");
 
+    /*
+    // Reject outdated version blocks when 95% (75% on testnet) of the network has upgraded:
+    for (int32_t version = 2; version < 5; ++version) // check for version 2, 3 and 4 upgrades
+        if (block.nVersion < version && IsSuperMajority(version, pindexPrev, consensusParams.nMajorityRejectBlockOutdated, consensusParams))
+            return state.Invalid(false, REJECT_OBSOLETE, strprintf("bad-version(0x%08x)", version - 1),
+                                 strprintf("rejected nVersion=0x%08x block", version - 1));
+    */
+
     return true;
 }
 
diff --git a/src/primitives/block.cpp b/src/primitives/block.cpp
index 57244f533..d01ceab67 100644
--- a/src/primitives/block.cpp
+++ b/src/primitives/block.cpp
@@ -28,7 +28,7 @@ uint256 CBlockHeader::GetPoWHash() const
 std::string CBlock::ToString() const
 {
     std::stringstream s;
-    s << strprintf("CBlock(hash=%s, ver=%d, hashPrevBlock=%s, hashMerkleRoot=%s, nTime=%u, nBits=%08x, nNonce=%u, vtx=%u, vchBlockSig=%s)\n",
+    s << strprintf("CBlock(hash=%s, ver=0x%08x, hashPrevBlock=%s, hashMerkleRoot=%s, nTime=%u, nBits=%08x, nNonce=%u, vtx=%u, vchBlockSig=%s)\n",
         GetHash().ToString(),
         nVersion,
         hashPrevBlock.ToString(),