diff --git a/src/chainparams.cpp b/src/chainparams.cpp
index 60a1aac87..bb45ce6a6 100755
--- a/src/chainparams.cpp
+++ b/src/chainparams.cpp
@@ -352,8 +352,8 @@ public:
 
         consensus.fPowAllowMinDifficultyBlocks = true;
         consensus.fPowNoRetargeting = true;
-        consensus.nRuleChangeActivationThreshold = 432; // 75% for testchains
-        consensus.nMinerConfirmationWindow = 576; // Faster than normal for regtest (144 instead of 2016)
+        consensus.nRuleChangeActivationThreshold = 108; // 75% for testchains
+        consensus.nMinerConfirmationWindow = 144; // Faster than normal for regtest (144 instead of 2016)
         consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].bit = 28;
         consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nStartTime = 0;
         consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nTimeout = 999999999999ULL;
diff --git a/test/functional/bip68-112-113-p2p.py b/test/functional/bip68-112-113-p2p.py
index 5a322e8c0..44904bbfd 100755
--- a/test/functional/bip68-112-113-p2p.py
+++ b/test/functional/bip68-112-113-p2p.py
@@ -104,7 +104,7 @@ class BIP68_112_113Test(ComparisonTestFramework):
         test.run()
 
     def send_generic_input_tx(self, node, coinbases):
-        amount = Decimal("49.99")
+        amount = Decimal("99.99")
         return node.sendrawtransaction(ToHex(self.sign_transaction(node, self.create_transaction(node, node.getblock(coinbases.pop())['tx'][0], self.nodeaddress, amount))))
 
     def create_transaction(self, node, txid, to_address, amount):
diff --git a/test/functional/blockchain.py b/test/functional/blockchain.py
index a7034e6bc..b72150575 100755
--- a/test/functional/blockchain.py
+++ b/test/functional/blockchain.py
@@ -59,8 +59,7 @@ class BlockchainTest(BitcoinTestFramework):
     def _test_gettxoutsetinfo(self):
         node = self.nodes[0]
         res = node.gettxoutsetinfo()
-
-        assert_equal(res['total_amount'], Decimal('8725.00000000'))
+        assert_equal(res['total_amount'], Decimal('17450.00000000'))
         assert_equal(res['transactions'], 200)
         assert_equal(res['height'], 200)
         assert_equal(res['txouts'], 200)
diff --git a/test/functional/fundrawtransaction.py b/test/functional/fundrawtransaction.py
index 1f5427ca4..86e401b04 100755
--- a/test/functional/fundrawtransaction.py
+++ b/test/functional/fundrawtransaction.py
@@ -51,7 +51,7 @@ class RawTransactionsTest(BitcoinTestFramework):
         self.sync_all()
 
         # ensure that setting changePosition in fundraw with an exact match is handled properly
-        rawmatch = self.nodes[2].createrawtransaction([], {self.nodes[2].getnewaddress():50})
+        rawmatch = self.nodes[2].createrawtransaction([], {self.nodes[2].getnewaddress():100})
         rawmatch = self.nodes[2].fundrawtransaction(rawmatch, {"changePosition":1, "subtractFeeFromOutputs":[0]})
         assert_equal(rawmatch["changepos"], -1)
 
@@ -498,7 +498,7 @@ class RawTransactionsTest(BitcoinTestFramework):
         self.sync_all()
 
         # make sure funds are received at node1
-        assert_equal(oldBalance+Decimal('51.10000000'), self.nodes[0].getbalance())
+        assert_equal(oldBalance+Decimal('101.10000000'), self.nodes[0].getbalance())
 
 
         ###############################################
@@ -558,7 +558,7 @@ class RawTransactionsTest(BitcoinTestFramework):
         self.sync_all()
         self.nodes[0].generate(1)
         self.sync_all()
-        assert_equal(oldBalance+Decimal('50.19000000'), self.nodes[0].getbalance()) #0.19+block reward
+        assert_equal(oldBalance+Decimal('100.19000000'), self.nodes[0].getbalance()) #0.19+block reward
 
         #####################################################
         # test fundrawtransaction with OP_RETURN and no vin #
diff --git a/test/functional/invalidblockrequest.py b/test/functional/invalidblockrequest.py
index eabc0db8d..a414761ff 100755
--- a/test/functional/invalidblockrequest.py
+++ b/test/functional/invalidblockrequest.py
@@ -102,7 +102,7 @@ class InvalidBlockRequestTest(ComparisonTestFramework):
         '''
         block3 = create_block(self.tip, create_coinbase(height), self.block_time)
         self.block_time += 1
-        block3.vtx[0].vout[0].nValue = 100 * COIN # Too high!
+        block3.vtx[0].vout[0].nValue = 200 * COIN # Too high!
         block3.vtx[0].sha256=None
         block3.vtx[0].calc_sha256()
         block3.hashMerkleRoot = block3.calc_merkle_root()
diff --git a/test/functional/mempool_reorg.py b/test/functional/mempool_reorg.py
index 937bf4bab..15fc64400 100755
--- a/test/functional/mempool_reorg.py
+++ b/test/functional/mempool_reorg.py
@@ -41,15 +41,15 @@ class MempoolCoinbaseTest(BitcoinTestFramework):
         # and make sure the mempool code behaves correctly.
         b = [ self.nodes[0].getblockhash(n) for n in range(101, 105) ]
         coinbase_txids = [ self.nodes[0].getblock(h)['tx'][0] for h in b ]
-        spend_101_raw = create_tx(self.nodes[0], coinbase_txids[1], node1_address, 49.99)
-        spend_102_raw = create_tx(self.nodes[0], coinbase_txids[2], node0_address, 49.99)
-        spend_103_raw = create_tx(self.nodes[0], coinbase_txids[3], node0_address, 49.99)
+        spend_101_raw = create_tx(self.nodes[0], coinbase_txids[1], node1_address, 99.99)
+        spend_102_raw = create_tx(self.nodes[0], coinbase_txids[2], node0_address, 99.99)
+        spend_103_raw = create_tx(self.nodes[0], coinbase_txids[3], node0_address, 99.99)
 
         # Create a transaction which is time-locked to two blocks in the future
-        timelock_tx = self.nodes[0].createrawtransaction([{"txid": coinbase_txids[0], "vout": 0}], {node0_address: 49.99})
+        timelock_tx = self.nodes[0].createrawtransaction([{"txid": coinbase_txids[0], "vout": 0}], {node0_address: 99.99})
         # Set the time lock
         timelock_tx = timelock_tx.replace("ffffffff", "11111191", 1)
-        timelock_tx = timelock_tx[:-8] + hex(self.nodes[0].getblockcount() + 2)[2:] + "000000"
+        timelock_tx = timelock_tx[:-10] + hex(self.nodes[0].getblockcount() + 2)[2:] + "00000000"
         timelock_tx = self.nodes[0].signrawtransaction(timelock_tx)["hex"]
         # This will raise an exception because the timelock transaction is too immature to spend
         assert_raises_jsonrpc(-26, "non-final", self.nodes[0].sendrawtransaction, timelock_tx)
@@ -62,8 +62,8 @@ class MempoolCoinbaseTest(BitcoinTestFramework):
         assert_raises_jsonrpc(-26,'non-final', self.nodes[0].sendrawtransaction, timelock_tx)
 
         # Create 102_1 and 103_1:
-        spend_102_1_raw = create_tx(self.nodes[0], spend_102_id, node1_address, 49.98)
-        spend_103_1_raw = create_tx(self.nodes[0], spend_103_id, node1_address, 49.98)
+        spend_102_1_raw = create_tx(self.nodes[0], spend_102_id, node1_address, 99.98)
+        spend_103_1_raw = create_tx(self.nodes[0], spend_103_id, node1_address, 99.98)
 
         # Broadcast and mine 103_1:
         spend_103_1_id = self.nodes[0].sendrawtransaction(spend_103_1_raw)
diff --git a/test/functional/mempool_resurrect_test.py b/test/functional/mempool_resurrect_test.py
index a2f6228df..843d80ea5 100755
--- a/test/functional/mempool_resurrect_test.py
+++ b/test/functional/mempool_resurrect_test.py
@@ -31,13 +31,13 @@ class MempoolCoinbaseTest(BitcoinTestFramework):
 
         b = [ self.nodes[0].getblockhash(n) for n in range(1, 4) ]
         coinbase_txids = [ self.nodes[0].getblock(h)['tx'][0] for h in b ]
-        spends1_raw = [ create_tx(self.nodes[0], txid, node0_address, 49.99) for txid in coinbase_txids ]
+        spends1_raw = [ create_tx(self.nodes[0], txid, node0_address, 99.99) for txid in coinbase_txids ]
         spends1_id = [ self.nodes[0].sendrawtransaction(tx) for tx in spends1_raw ]
 
         blocks = []
         blocks.extend(self.nodes[0].generate(1))
 
-        spends2_raw = [ create_tx(self.nodes[0], txid, node0_address, 49.98) for txid in spends1_id ]
+        spends2_raw = [ create_tx(self.nodes[0], txid, node0_address, 99.98) for txid in spends1_id ]
         spends2_id = [ self.nodes[0].sendrawtransaction(tx) for tx in spends2_raw ]
 
         blocks.extend(self.nodes[0].generate(1))
diff --git a/test/functional/mempool_spendcoinbase.py b/test/functional/mempool_spendcoinbase.py
index 277ea45ad..3edf17768 100755
--- a/test/functional/mempool_spendcoinbase.py
+++ b/test/functional/mempool_spendcoinbase.py
@@ -34,7 +34,7 @@ class MempoolSpendCoinbaseTest(BitcoinTestFramework):
         # is too immature to spend.
         b = [ self.nodes[0].getblockhash(n) for n in range(101, 103) ]
         coinbase_txids = [ self.nodes[0].getblock(h)['tx'][0] for h in b ]
-        spends_raw = [ create_tx(self.nodes[0], txid, node0_address, 49.99) for txid in coinbase_txids ]
+        spends_raw = [ create_tx(self.nodes[0], txid, node0_address, 99.99) for txid in coinbase_txids ]
 
         spend_101_id = self.nodes[0].sendrawtransaction(spends_raw[0])
 
diff --git a/test/functional/merkle_blocks.py b/test/functional/merkle_blocks.py
index bcc65c840..6fef80aed 100755
--- a/test/functional/merkle_blocks.py
+++ b/test/functional/merkle_blocks.py
@@ -35,9 +35,9 @@ class MerkleBlockTest(BitcoinTestFramework):
         assert_equal(self.nodes[2].getbalance(), 0)
 
         node0utxos = self.nodes[0].listunspent(1)
-        tx1 = self.nodes[0].createrawtransaction([node0utxos.pop()], {self.nodes[1].getnewaddress(): 49.99})
+        tx1 = self.nodes[0].createrawtransaction([node0utxos.pop()], {self.nodes[1].getnewaddress(): 99.99})
         txid1 = self.nodes[0].sendrawtransaction(self.nodes[0].signrawtransaction(tx1)["hex"])
-        tx2 = self.nodes[0].createrawtransaction([node0utxos.pop()], {self.nodes[1].getnewaddress(): 49.99})
+        tx2 = self.nodes[0].createrawtransaction([node0utxos.pop()], {self.nodes[1].getnewaddress(): 99.99})
         txid2 = self.nodes[0].sendrawtransaction(self.nodes[0].signrawtransaction(tx2)["hex"])
         # This will raise an exception because the transaction is not yet in a block
         assert_raises_jsonrpc(-5, "Transaction not yet in block", self.nodes[0].gettxoutproof, [txid1])
@@ -56,7 +56,7 @@ class MerkleBlockTest(BitcoinTestFramework):
         assert_equal(self.nodes[2].verifytxoutproof(self.nodes[2].gettxoutproof([txid1, txid2], blockhash)), txlist)
 
         txin_spent = self.nodes[1].listunspent(1).pop()
-        tx3 = self.nodes[1].createrawtransaction([txin_spent], {self.nodes[0].getnewaddress(): 49.98})
+        tx3 = self.nodes[1].createrawtransaction([txin_spent], {self.nodes[0].getnewaddress(): 99.98})
         txid3 = self.nodes[0].sendrawtransaction(self.nodes[1].signrawtransaction(tx3)["hex"])
         self.nodes[0].generate(1)
         self.sync_all()
diff --git a/test/functional/multiwallet.py b/test/functional/multiwallet.py
index 5679f4050..8c1bafe07 100755
--- a/test/functional/multiwallet.py
+++ b/test/functional/multiwallet.py
@@ -46,7 +46,7 @@ class MultiWalletTest(BitcoinTestFramework):
 
         # check w1 wallet balance
         w1_info = w1.getwalletinfo()
-        assert_equal(w1_info['immature_balance'], 50)
+        assert_equal(w1_info['immature_balance'], 100)
         w1_name = w1_info['walletname']
         assert_equal(w1_name, "w1")
 
@@ -64,7 +64,7 @@ class MultiWalletTest(BitcoinTestFramework):
         assert_equal({"w1", "w2", "w3"}, {w1_name, w2_name, w3_name})
 
         w1.generate(101)
-        assert_equal(w1.getbalance(), 100)
+        assert_equal(w1.getbalance(), 200)
         assert_equal(w2.getbalance(), 0)
         assert_equal(w3.getbalance(), 0)
 
diff --git a/test/functional/p2p-fullblocktest.py b/test/functional/p2p-fullblocktest.py
index 4d8ff65e2..6bed01a38 100755
--- a/test/functional/p2p-fullblocktest.py
+++ b/test/functional/p2p-fullblocktest.py
@@ -359,7 +359,7 @@ class FullBlockTest(ComparisonTestFramework):
         tip(15)
         b23 = block(23, spend=out[6])
         tx = CTransaction()
-        script_length = MAX_BLOCK_BASE_SIZE - len(b23.serialize()) - 69
+        script_length = MAX_BLOCK_BASE_SIZE - len(b23.serialize()) - 69 - 1 #subtract 1 for txComment byte
         script_output = CScript([b'\x00' * script_length])
         tx.vout.append(CTxOut(0, script_output))
         tx.vin.append(CTxIn(COutPoint(b23.vtx[1].sha256, 0)))
@@ -372,7 +372,7 @@ class FullBlockTest(ComparisonTestFramework):
         # Make the next block one byte bigger and check that it fails
         tip(15)
         b24 = block(24, spend=out[6])
-        script_length = MAX_BLOCK_BASE_SIZE - len(b24.serialize()) - 69
+        script_length = MAX_BLOCK_BASE_SIZE - len(b24.serialize()) - 69 - 1 #subtract 1 for txComment byte
         script_output = CScript([b'\x00' * (script_length+1)])
         tx.vout = [CTxOut(0, script_output)]
         b24 = update_block(24, [tx])
@@ -788,7 +788,7 @@ class FullBlockTest(ComparisonTestFramework):
         assert_equal(len(b56p2.vtx),6)
         b56p2 = update_block("b56p2", [tx3, tx4])
         yield rejected(RejectResult(16, b'bad-txns-duplicate'))
-
+        
         tip("57p2")
         yield accepted()
 
@@ -813,10 +813,10 @@ class FullBlockTest(ComparisonTestFramework):
         b58 = update_block(58, [tx])
         yield rejected(RejectResult(16, b'bad-txns-inputs-missingorspent'))
 
-        # tx with output value > input value out of range
+     # tx with output value > input value out of range
         tip(57)
         b59 = block(59)
-        tx = create_and_sign_tx(out[17].tx, out[17].n, 51*COIN)
+        tx = create_and_sign_tx(out[17].tx, out[17].n, 101*COIN)
         b59 = update_block(59, [tx])
         yield rejected(RejectResult(16, b'bad-txns-in-belowout'))
 
@@ -901,7 +901,7 @@ class FullBlockTest(ComparisonTestFramework):
         tx = CTransaction()
 
         # use canonical serialization to calculate size
-        script_length = MAX_BLOCK_BASE_SIZE - len(b64a.normal_serialize()) - 69
+        script_length = MAX_BLOCK_BASE_SIZE - len(b64a.normal_serialize()) - 69 - 1  #subtract 1 for txComment byte
         script_output = CScript([b'\x00' * script_length])
         tx.vout.append(CTxOut(0, script_output))
         tx.vin.append(CTxIn(COutPoint(b64a.vtx[1].sha256, 0)))
@@ -1250,7 +1250,7 @@ class FullBlockTest(ComparisonTestFramework):
             for i in range(89, LARGE_REORG_SIZE + 89):
                 b = block(i, spend)
                 tx = CTransaction()
-                script_length = MAX_BLOCK_BASE_SIZE - len(b.serialize()) - 69
+                script_length = MAX_BLOCK_BASE_SIZE - len(b.serialize()) - 69 - 1  #subtract 1 for txComment byte
                 script_output = CScript([b'\x00' * script_length])
                 tx.vout.append(CTxOut(0, script_output))
                 tx.vin.append(CTxIn(COutPoint(b.vtx[1].sha256, 0)))
diff --git a/test/functional/p2p-segwit.py b/test/functional/p2p-segwit.py
index 435b6accb..0d2266bb7 100755
--- a/test/functional/p2p-segwit.py
+++ b/test/functional/p2p-segwit.py
@@ -758,6 +758,10 @@ class SegWitTest(BitcoinTestFramework):
                 if flags & 1:
                     r += self.wit.serialize()
                 r += struct.pack("<I", self.nLockTime)
+                if self.nVersion >= 2:
+                    r += ser_compact_size(len(self.txComment))
+                    if len(self.txComment) > 0:
+                        r += struct.pack("<s", self.txComment)
                 return r
 
         tx2 = BrokenCTransaction()
diff --git a/test/functional/test_framework/blocktools.py b/test/functional/test_framework/blocktools.py
old mode 100644
new mode 100755
index 5dcf516dc..e60614d3d
--- a/test/functional/test_framework/blocktools.py
+++ b/test/functional/test_framework/blocktools.py
@@ -73,7 +73,7 @@ def create_coinbase(height, pubkey = None):
     coinbase.vin.append(CTxIn(COutPoint(0, 0xffffffff), 
                 ser_string(serialize_script_num(height)), 0xffffffff))
     coinbaseoutput = CTxOut()
-    coinbaseoutput.nValue = 50 * COIN
+    coinbaseoutput.nValue = 100 * COIN
     halvings = int(height/150) # regtest
     coinbaseoutput.nValue >>= halvings
     if (pubkey != None):
diff --git a/test/functional/test_framework/mininode.py b/test/functional/test_framework/mininode.py
index 9b2cb7fca..2bb7ab6f1 100755
--- a/test/functional/test_framework/mininode.py
+++ b/test/functional/test_framework/mininode.py
@@ -427,13 +427,14 @@ class CTxWitness(object):
 class CTransaction(object):
     def __init__(self, tx=None):
         if tx is None:
-            self.nVersion = 1
+            self.nVersion = 2
             self.vin = []
             self.vout = []
             self.wit = CTxWitness()
             self.nLockTime = 0
             self.sha256 = None
             self.hash = None
+            self.txComment = ""
         else:
             self.nVersion = tx.nVersion
             self.vin = copy.deepcopy(tx.vin)
@@ -442,6 +443,7 @@ class CTransaction(object):
             self.sha256 = tx.sha256
             self.hash = tx.hash
             self.wit = copy.deepcopy(tx.wit)
+            self.txComment = '%s' % tx.txComment
 
     def deserialize(self, f):
         self.nVersion = struct.unpack("<i", f.read(4))[0]
@@ -460,6 +462,12 @@ class CTransaction(object):
             self.wit.vtxinwit = [CTxInWitness() for i in range(len(self.vin))]
             self.wit.deserialize(f)
         self.nLockTime = struct.unpack("<I", f.read(4))[0]
+        if self.nVersion >= 2:
+            tx_comment_len = deser_compact_size(f)
+            if tx_comment_len > 0:
+                self.txComment = struct.unpack("<s", f.read(tx_comment_len))[0]
+            else:
+                self.txComment = ""
         self.sha256 = None
         self.hash = None
 
@@ -469,6 +477,11 @@ class CTransaction(object):
         r += ser_vector(self.vin)
         r += ser_vector(self.vout)
         r += struct.pack("<I", self.nLockTime)
+        if self.nVersion >= 2:
+            r += ser_compact_size(len(self.txComment))
+            if len(self.txComment) > 0:
+                r += struct.pack("<s", self.txComment)
+
         return r
 
     # Only serialize with witness when explicitly called for
@@ -492,6 +505,11 @@ class CTransaction(object):
                     self.wit.vtxinwit.append(CTxInWitness())
             r += self.wit.serialize()
         r += struct.pack("<I", self.nLockTime)
+        if self.nVersion >= 2:
+            r += ser_compact_size(len(self.txComment))
+            if len(self.txComment) > 0:
+                r += struct.pack("<s", self.txComment)
+        
         return r
 
     # Regular serialization is without witness -- must explicitly
@@ -1674,8 +1692,8 @@ class NodeConn(asyncore.dispatcher):
         b"blocktxn": msg_blocktxn
     }
     MAGIC_BYTES = {
-        "mainnet": b"\xfb\xc0\xb6\xdb",   # mainnet
-        "testnet3": b"\xfc\xc1\xb7\xdc",  # testnet3
+        "mainnet": b"\xfd\xc0\xa5\xf1",   # mainnet
+        "testnet3": b"\xfd\xc0\x5a\xf2",  # testnet3
         "regtest": b"\xfa\xbf\xb5\xda",   # regtest
     }
 
diff --git a/test/functional/test_framework/util.py b/test/functional/test_framework/util.py
old mode 100644
new mode 100755
index 7adee0073..436df1136
--- a/test/functional/test_framework/util.py
+++ b/test/functional/test_framework/util.py
@@ -24,7 +24,7 @@ logger = logging.getLogger("TestFramework.utils")
 
 def assert_fee_amount(fee, tx_size, fee_per_kB):
     """Assert the fee was in range"""
-    target_fee = tx_size * fee_per_kB / 1000
+    target_fee = round(tx_size * fee_per_kB / 1000,30)
     if fee < target_fee:
         raise AssertionError("Fee of %s BTC too low! (Should be %s BTC)" % (str(fee), str(target_fee)))
     # allow the wallet's estimation to be at most 2 bytes off