From c95dba4f9c46bbc6a3755f5b2038853251cb67af Mon Sep 17 00:00:00 2001
From: khalahan <khal@dot-bit.org>
Date: Sat, 1 Mar 2014 23:54:51 +0100
Subject: [PATCH 1/2] Testnet difficulty calculation changes, to take effect
 Mar 15 2014 Allow mining of min-difficulty blocks if 20 minutes have gone by
 without mining a regular-difficulty block. Normal rules apply every 2016
 blocks, though, so there may be a very-slow-to-confirm block at the
 difficulty-adjustment blocks.

---
 src/main.cpp | 29 +++++++++++++++++++++++++----
 1 file changed, 25 insertions(+), 4 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index 26331adb5..1fe6ec39f 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -746,19 +746,40 @@ int64 static GetBlockValue(int nHeight, int64 nFees)
     return nSubsidy + nFees;
 }
 
-unsigned int static GetNextWorkRequired(const CBlockIndex* pindexLast)
+unsigned int static GetNextWorkRequired(const CBlockIndex* pindexLast, const CBlock *pblock)
 {
     const int64 nTargetTimespan = 14 * 24 * 60 * 60; // two weeks
     const int64 nTargetSpacing = 10 * 60;
     const int64 nInterval = nTargetTimespan / nTargetSpacing;
 
+    unsigned int nProofOfWorkLimit = bnProofOfWorkLimit.GetCompact();
+
     // Genesis block
     if (pindexLast == NULL)
-        return bnProofOfWorkLimit.GetCompact();
+        return nProofOfWorkLimit;
 
     // Only change once per interval
     if ((pindexLast->nHeight+1) % nInterval != 0)
+    {
+        // Special rules for testnet after 15 Mar 2014:
+        if (fTestNet && pblock->nTime > 1394838000)
+        {
+            // If the new block's timestamp is more than 2* 10 minutes
+            // then allow mining of a min-difficulty block.
+            if (pblock->nTime - pindexLast->nTime > nTargetSpacing*2)
+                return nProofOfWorkLimit;
+            else
+            {
+                // Return the last non-special-min-difficulty-rules-block
+                const CBlockIndex* pindex = pindexLast;
+                while (pindex->pprev && pindex->nHeight % nInterval != 0 && pindex->nBits == nProofOfWorkLimit)
+                    pindex = pindex->pprev;
+                return pindex->nBits;
+            }
+        }
+
         return pindexLast->nBits;
+    }
 
     // Go back the full period unless it's the first retarget after genesis. Code courtesy of ArtForz
 
@@ -1526,7 +1547,7 @@ bool CBlock::AcceptBlock()
     int nHeight = pindexPrev->nHeight+1;
 
     // Check proof of work
-    if (nBits != GetNextWorkRequired(pindexPrev))
+    if (nBits != GetNextWorkRequired(pindexPrev, this))
         return error("AcceptBlock() : incorrect proof of work");
 
     // Check timestamp against prev
@@ -3125,7 +3146,7 @@ CBlock* CreateNewBlock(CReserveKey& reservekey)
     pblock->hashPrevBlock  = pindexPrev->GetBlockHash();
     pblock->hashMerkleRoot = pblock->BuildMerkleTree();
     pblock->nTime          = max(pindexPrev->GetMedianTimePast()+1, GetAdjustedTime());
-    pblock->nBits          = GetNextWorkRequired(pindexPrev);
+    pblock->nBits          = GetNextWorkRequired(pindexPrev, pblock.get());
     pblock->nNonce         = 0;
 
     return pblock.release();

From 8f64b47f58bc701ac0ae4aed53eaabc4c9337bf6 Mon Sep 17 00:00:00 2001
From: khalahan <khal@dot-bit.org>
Date: Sun, 2 Mar 2014 00:15:12 +0100
Subject: [PATCH 2/2] Update version to 0.3.73

---
 src/serialize.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/serialize.h b/src/serialize.h
index 2a8e0ff80..a6c80d23e 100644
--- a/src/serialize.h
+++ b/src/serialize.h
@@ -35,7 +35,7 @@ class CDataStream;
 class CAutoFile;
 static const unsigned int MAX_SIZE = 0x02000000;
 
-static const int VERSION = 37200;
+static const int VERSION = 37300;
 static const char* pszSubVer = "";
 static const bool VERSION_IS_BETA = false;