stale_target:

diff --git a/src/pow.cpp b/src/pow.cpp
index 45237b2..e444c2a 100644
--- a/src/pow.cpp
+++ b/src/pow.cpp
@@ -35,6 +35,10 @@ unsigned int GetNextWorkRequired(const CBlockIndex* pindexLast, const CBlockHead
                 return pindex->nBits;
             }
         }
+        else if ((pindexLast->nHeight + 1) >= 1821 && pblock->GetBlockTime() > pindexLast->GetBlockTime() + params.nPowTargetSpacing*10)
+        {
+            return CalculateNextWorkRequiredStale(pindexLast, (pblock->GetBlockTime() - pindexLast->GetBlockTime()) / params.nPowTargetSpacing*10, params);
+        }
         return pindexLast->nBits;
     }
 
@@ -72,6 +76,29 @@ unsigned int CalculateNextWorkRequired(const CBlockIndex* pindexLast, int64_t nF
     return bnNew.GetCompact();
 }
 
+unsigned int CalculateNextWorkRequiredStale(const CBlockIndex* pindexLast, int shift, const Consensus::Params& params)
+{
+    if (params.fPowNoRetargeting)
+        return pindexLast->nBits;
+
+    // Retarget
+    const arith_uint256 bnPowLimit = UintToArith256(params.powLimit);
+    arith_uint256 bnNew;
+    bnNew.SetCompact(pindexLast->nBits);
+
+    for (int i=0; i<shift; i++)
+    {
+        bnNew *= 2;
+        if (bnNew > bnPowLimit)
+        {
+            bnNew = bnPowLimit;
+            break;
+        }
+    }
+
+    return bnNew.GetCompact();
+}
+
 bool CheckProofOfWork(uint256 hash, unsigned int nBits, const Consensus::Params& params)
 {
     bool fNegative;