From 8740cea98ac063e8849175920bd9e76aa8aa6bdd Mon Sep 17 00:00:00 2001
From: Anthony Fieroni <bvbfan@abv.bg>
Date: Mon, 24 Jan 2022 11:14:22 +0000
Subject: [PATCH 1/5] Don't count minted coins in block stats (#1048)

Signed-off-by: Anthony Fieroni <bvbfan@abv.bg>

Co-authored-by: Jouzo <jdesclercs@gmail.com>
---
 src/rpc/blockchain.cpp                         | 12 ++++++++++--
 test/functional/feature_accounts_validation.py |  4 ++++
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index e6d506137d..e533e1a23e 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -16,6 +16,7 @@
 #include <hash.h>
 #include <index/blockfilterindex.h>
 #include <masternodes/masternodes.h>
+#include <masternodes/mn_checks.h>
 #include <policy/feerate.h>
 #include <policy/policy.h>
 #include <policy/rbf.h>
@@ -1883,8 +1884,15 @@ static UniValue getblockstats(const JSONRPCRequest& request)
 
         CAmount tx_total_out = 0;
         if (loop_outputs) {
-            for (const CTxOut& out : tx->vout) {
-                tx_total_out += out.nValue;
+            auto mintingOutputsStart = ~0u;
+            if (auto accountToUtxos = GetAccountToUtxosMsg(*tx)) {
+                mintingOutputsStart = accountToUtxos->mintingOutputsStart;
+            }
+            for (size_t i = 0; i < tx->vout.size(); ++i) {
+                const auto& out = tx->vout[i];
+                if (i < mintingOutputsStart) {
+                    tx_total_out += out.nValue;
+                }
                 utxo_size_inc += GetSerializeSize(out, PROTOCOL_VERSION) + PER_UTXO_OVERHEAD;
             }
         }
diff --git a/test/functional/feature_accounts_validation.py b/test/functional/feature_accounts_validation.py
index 7695738a96..5265d8a50d 100755
--- a/test/functional/feature_accounts_validation.py
+++ b/test/functional/feature_accounts_validation.py
@@ -46,6 +46,10 @@ def run_test(self):
         node.generate(1)
         self.sync_all()
 
+        stats = node.getblockstats(blockcount + 1)
+        assert_equal(stats["total_out"], 18199952120)
+        assert_equal(stats["totalfee"], 25880)
+
         # Check the blockchain has extended as expected
         assert_equal(node1.getblockcount(), blockcount + 1)
 

From 847b6b537354e31470bf58c8da7bc8eaabd09faf Mon Sep 17 00:00:00 2001
From: Anthony Fieroni <bvbfan@abv.bg>
Date: Mon, 24 Jan 2022 14:24:42 +0000
Subject: [PATCH 2/5] Fix pool rewards starting after actual share (#948)

* Fix pool rewards starting after actual share

Signed-off-by: Anthony Fieroni <bvbfan@abv.bg>

* Adjust pool reward height to Fort Canning Hill

Signed-off-by: Anthony Fieroni <bvbfan@abv.bg>

Co-authored-by: Prasanna Loganathar <pvl@prasannavl.com>
---
 src/masternodes/poolpairs.cpp | 28 ++++++++++++++++++++++++----
 src/test/storage_tests.cpp    | 16 ++++++++++++++++
 2 files changed, 40 insertions(+), 4 deletions(-)

diff --git a/src/masternodes/poolpairs.cpp b/src/masternodes/poolpairs.cpp
index da6f4a5947..30ac316b4f 100644
--- a/src/masternodes/poolpairs.cpp
+++ b/src/masternodes/poolpairs.cpp
@@ -218,6 +218,23 @@ void ReadValueMoveToNext(TIterator & it, DCT_ID poolId, ValueType & value, uint3
     }
 }
 
+template<typename TIterator>
+void FindSuitablePoolRewards(TIterator & it, PoolHeightKey poolKey, uint32_t endHeight, uint32_t & height) {
+
+    static const auto poolStartHeight = uint32_t(Params().GetConsensus().FortCanningHillHeight);
+    poolKey.height = std::max(poolKey.height, poolStartHeight);
+
+    while (!it.Valid() && poolKey.height < endHeight) {
+        poolKey.height++;
+        it.Seek(poolKey);
+    }
+    if (it.Valid() && it.Key().poolID == poolKey.poolID) {
+        height = it.Key().height;
+    } else {
+        height = UINT_MAX;
+    }
+}
+
 void CPoolPairView::CalculatePoolRewards(DCT_ID const & poolId, std::function<CAmount()> onLiquidity, uint32_t begin, uint32_t end, std::function<void(RewardType, CTokenAmount, uint32_t)> onReward) {
     if (begin >= end) {
         return;
@@ -232,10 +249,14 @@ void CPoolPairView::CalculatePoolRewards(DCT_ID const & poolId, std::function<CA
 
     CAmount poolReward = 0;
     CAmount poolLoanReward = 0;
+
     auto nextPoolReward = begin;
-    auto nextPoolLoanReward = begin;
     auto itPoolReward = LowerBound<ByPoolReward>(poolKey);
+    FindSuitablePoolRewards(itPoolReward, poolKey, end, nextPoolReward);
+
+    auto nextPoolLoanReward = begin;
     auto itPoolLoanReward = LowerBound<ByPoolLoanReward>(poolKey);
+    FindSuitablePoolRewards(itPoolLoanReward, poolKey, end, nextPoolLoanReward);
 
     CAmount totalLiquidity = 0;
     auto nextTotalLiquidity = begin;
@@ -244,14 +265,13 @@ void CPoolPairView::CalculatePoolRewards(DCT_ID const & poolId, std::function<CA
     CBalances customRewards;
     auto nextCustomRewards = begin;
     auto itCustomRewards = LowerBound<ByCustomReward>(poolKey);
+    FindSuitablePoolRewards(itCustomRewards, poolKey, end, nextCustomRewards);
 
     PoolSwapValue poolSwap;
     auto nextPoolSwap = UINT_MAX;
     auto poolSwapHeight = UINT_MAX;
     auto itPoolSwap = LowerBound<ByPoolSwap>(poolKey);
-    if (itPoolSwap.Valid() && itPoolSwap.Key().poolID == poolId) {
-        nextPoolSwap = itPoolSwap.Key().height;
-    }
+    FindSuitablePoolRewards(itPoolSwap, poolKey, end, nextPoolSwap);
 
     for (auto height = begin; height < end;) {
         // find suitable pool liquidity
diff --git a/src/test/storage_tests.cpp b/src/test/storage_tests.cpp
index 601ac297e6..bba10c6a62 100644
--- a/src/test/storage_tests.cpp
+++ b/src/test/storage_tests.cpp
@@ -463,6 +463,22 @@ BOOST_AUTO_TEST_CASE(LowerBoundTest)
         BOOST_CHECK(it.Valid());
         BOOST_CHECK(it.Value().as<int>() == 2);
     }
+
+    {
+        CCustomCSView view(*pcustomcsview);
+        view.WriteBy<TestBackward>(TestBackward{5}, 1);
+        view.WriteBy<TestBackward>(TestBackward{6}, 2);
+
+        auto start = TestBackward{0};
+        auto it = view.LowerBound<TestBackward>(start);
+        while (!it.Valid()) {
+            start.n++;
+            it.Seek(start);
+        }
+        BOOST_REQUIRE(it.Valid());
+        BOOST_CHECK_EQUAL(start.n, 5);
+        BOOST_CHECK_EQUAL(it.Key().n, 5);
+    }
 }
 
 BOOST_AUTO_TEST_SUITE_END()

From 9bd0dfd0d345a792a38cdfeb485386a2c7ddddcc Mon Sep 17 00:00:00 2001
From: Mihailo Milenkovic <mihailo.milenkovic84@gmail.com>
Date: Mon, 24 Jan 2022 18:21:35 +0100
Subject: [PATCH 3/5] High precision interest calculation (#991)

* High precision interest calculation (#991)

Co-authored-by: Jouzo <jdesclercs@gmail.com>
Co-authored-by: Anthony Fieroni <bvbfan@abv.bg>
Co-authored-by: Prasanna Loganathar <pvl@prasannavl.com>
Co-authored-by: Peter John Bushnell <bushsolo@gmail.com>
Co-authored-by: D <55594560+hidiego@users.noreply.github.com>
Co-authored-by: Diego del Corral <hi@dcorral.com>
---
 src/arith_uint256.cpp                        |  56 +++-
 src/arith_uint256.h                          |  54 ++-
 src/masternodes/loan.cpp                     | 241 +++++++++----
 src/masternodes/loan.h                       |  52 ++-
 src/masternodes/masternodes.cpp              |   4 +-
 src/masternodes/masternodes.h                |   2 +-
 src/masternodes/mn_checks.cpp                |  21 +-
 src/masternodes/mn_rpc.cpp                   |   6 +
 src/masternodes/mn_rpc.h                     |   1 +
 src/masternodes/rpc_loan.cpp                 |  32 +-
 src/masternodes/rpc_vault.cpp                |   4 +-
 src/test/arith_uint256_tests.cpp             |  14 +-
 src/test/loan_tests.cpp                      |  18 +-
 src/uint256.cpp                              |  15 +-
 src/validation.cpp                           |  30 +-
 test/functional/feature_loan_low_interest.py | 334 +++++++++++++++++++
 test/functional/feature_loan_vault.py        |   4 +-
 test/functional/test_runner.py               |   1 +
 test/lint/lint-python-dead-code-whitelist    |   1 +
 19 files changed, 753 insertions(+), 137 deletions(-)
 create mode 100755 test/functional/feature_loan_low_interest.py

diff --git a/src/arith_uint256.cpp b/src/arith_uint256.cpp
index b11fffed10..b290c6b3b0 100644
--- a/src/arith_uint256.cpp
+++ b/src/arith_uint256.cpp
@@ -5,12 +5,16 @@
 
 #include <arith_uint256.h>
 
+#include <util/strencodings.h>
 #include <uint256.h>
 #include <crypto/common.h>
 
 #include <stdio.h>
 #include <string.h>
 
+template<unsigned int BITS>
+constexpr int base_uint<BITS>::WIDTH;
+
 template <unsigned int BITS>
 base_uint<BITS>::base_uint(const std::string& str)
 {
@@ -65,6 +69,27 @@ base_uint<BITS>& base_uint<BITS>::operator*=(uint32_t b32)
     return *this;
 }
 
+template <unsigned int BITS>
+base_uint<BITS>& base_uint<BITS>::operator*=(int32_t b32)
+{
+    (*this) *= uint32_t(b32);
+    return *this;
+}
+
+template <unsigned int BITS>
+base_uint<BITS>& base_uint<BITS>::operator*=(int64_t b64)
+{
+    (*this) *= base_uint(b64);
+    return *this;
+}
+
+template <unsigned int BITS>
+base_uint<BITS>& base_uint<BITS>::operator*=(uint64_t b64)
+{
+    (*this) *= base_uint(b64);
+    return *this;
+}
+
 template <unsigned int BITS>
 base_uint<BITS>& base_uint<BITS>::operator*=(const base_uint& b)
 {
@@ -148,13 +173,21 @@ double base_uint<BITS>::getdouble() const
 template <unsigned int BITS>
 std::string base_uint<BITS>::GetHex() const
 {
-    return ArithToUint256(*this).GetHex();
+    base_blob<BITS> b;
+
+    for(int x=0; x<WIDTH; ++x)
+        WriteLE32(b.begin() + x*4, pn[x]);
+    return b.GetHex();
 }
 
 template <unsigned int BITS>
 void base_uint<BITS>::SetHex(const char* psz)
 {
-    *this = UintToArith256(uint256S(psz));
+    base_blob<BITS> a;
+
+    a.SetHex(psz);
+    for(int x=0; x<WIDTH; ++x)
+        pn[x] = ReadLE32(a.begin() + x*4);
 }
 
 template <unsigned int BITS>
@@ -207,22 +240,11 @@ base_uint<BITS> base_uint<BITS>::sqrt() const
     return res;
 }
 
+// Explicit instantiations for base_uint<128>
+template class base_uint<128>;
+
 // Explicit instantiations for base_uint<256>
-template base_uint<256>::base_uint(const std::string&);
-template base_uint<256>& base_uint<256>::operator<<=(unsigned int);
-template base_uint<256>& base_uint<256>::operator>>=(unsigned int);
-template base_uint<256>& base_uint<256>::operator*=(uint32_t b32);
-template base_uint<256>& base_uint<256>::operator*=(const base_uint<256>& b);
-template base_uint<256>& base_uint<256>::operator/=(const base_uint<256>& b);
-template int base_uint<256>::CompareTo(const base_uint<256>&) const;
-template bool base_uint<256>::EqualTo(uint64_t) const;
-template double base_uint<256>::getdouble() const;
-template std::string base_uint<256>::GetHex() const;
-template std::string base_uint<256>::ToString() const;
-template void base_uint<256>::SetHex(const char*);
-template void base_uint<256>::SetHex(const std::string&);
-template unsigned int base_uint<256>::bits() const;
-template base_uint<256> base_uint<256>::sqrt() const;
+template class base_uint<256>;
 
 // This implementation directly uses shifts instead of going
 // through an intermediate MPI representation.
diff --git a/src/arith_uint256.h b/src/arith_uint256.h
index 196c000d76..f46d9ec84c 100644
--- a/src/arith_uint256.h
+++ b/src/arith_uint256.h
@@ -30,6 +30,8 @@ class base_uint
     uint32_t pn[WIDTH];
 public:
 
+    template<unsigned int BITS1> friend class base_uint;
+
     base_uint()
     {
         static_assert(BITS/32 > 0 && BITS%32 == 0, "Template parameter BITS must be a positive multiple of 32.");
@@ -42,15 +44,7 @@ class base_uint
     {
         static_assert(BITS/32 > 0 && BITS%32 == 0, "Template parameter BITS must be a positive multiple of 32.");
 
-        for (int i = 0; i < WIDTH; i++)
-            pn[i] = b.pn[i];
-    }
-
-    base_uint& operator=(const base_uint& b)
-    {
-        for (int i = 0; i < WIDTH; i++)
-            pn[i] = b.pn[i];
-        return *this;
+        (*this) = b;
     }
 
     base_uint(uint64_t b)
@@ -63,6 +57,12 @@ class base_uint
             pn[i] = 0;
     }
 
+    template<unsigned int BITS1>
+    base_uint(const base_uint<BITS1>& b)
+    {
+        (*this) = b;
+    }
+
     explicit base_uint(const std::string& str);
 
     const base_uint operator~() const
@@ -84,6 +84,24 @@ class base_uint
 
     double getdouble() const;
 
+    template<unsigned int BITS1>
+    base_uint& operator=(const base_uint<BITS1>& b)
+    {
+        auto width = std::min(WIDTH, base_uint<BITS1>::WIDTH);
+        for (int i = 0; i < width; i++)
+            pn[i] = b.pn[i];
+        for (int i = width; i < WIDTH; i++)
+            pn[i] = 0;
+        return *this;
+    }
+
+    base_uint& operator=(const base_uint& b)
+    {
+        for (int i = 0; i < WIDTH; i++)
+            pn[i] = b.pn[i];
+        return *this;
+    }
+
     base_uint& operator=(uint64_t b)
     {
         pn[0] = (unsigned int)b;
@@ -165,7 +183,10 @@ class base_uint
         return *this;
     }
 
+    base_uint& operator*=(int32_t b32);
     base_uint& operator*=(uint32_t b32);
+    base_uint& operator*=(int64_t b64);
+    base_uint& operator*=(uint64_t b64);
     base_uint& operator*=(const base_uint& b);
     base_uint& operator/=(const base_uint& b);
 
@@ -215,7 +236,10 @@ class base_uint
     friend inline const base_uint operator^(const base_uint& a, const base_uint& b) { return base_uint(a) ^= b; }
     friend inline const base_uint operator>>(const base_uint& a, int shift) { return base_uint(a) >>= shift; }
     friend inline const base_uint operator<<(const base_uint& a, int shift) { return base_uint(a) <<= shift; }
+    friend inline const base_uint operator*(const base_uint& a, int32_t b) { return base_uint(a) *= b; }
     friend inline const base_uint operator*(const base_uint& a, uint32_t b) { return base_uint(a) *= b; }
+    friend inline const base_uint operator*(const base_uint& a, int64_t b) { return base_uint(a) *= b; }
+    friend inline const base_uint operator*(const base_uint& a, uint64_t b) { return base_uint(a) *= b; }
     friend inline bool operator==(const base_uint& a, const base_uint& b) { return memcmp(a.pn, b.pn, sizeof(a.pn)) == 0; }
     friend inline bool operator!=(const base_uint& a, const base_uint& b) { return memcmp(a.pn, b.pn, sizeof(a.pn)) != 0; }
     friend inline bool operator>(const base_uint& a, const base_uint& b) { return a.CompareTo(b) > 0; }
@@ -248,6 +272,18 @@ class base_uint
         static_assert(WIDTH >= 2, "Assertion WIDTH >= 2 failed (WIDTH = BITS / 32). BITS is a template parameter.");
         return pn[0] | (uint64_t)pn[1] << 32;
     }
+
+    template<typename Stream>
+    void Serialize(Stream& s) const
+    {
+        s.write((char*)pn, sizeof(pn));
+    }
+
+    template<typename Stream>
+    void Unserialize(Stream& s)
+    {
+        s.read((char*)pn, sizeof(pn));
+    }
 };
 
 /** 256-bit unsigned big integer. */
diff --git a/src/masternodes/loan.cpp b/src/masternodes/loan.cpp
index a53f302ca2..75f6bf3b25 100644
--- a/src/masternodes/loan.cpp
+++ b/src/masternodes/loan.cpp
@@ -169,15 +169,13 @@ Res CLoanView::EraseLoanScheme(const std::string& loanSchemeID)
     std::vector<uint64_t> loanUpdateHeights;
     ForEachDelayedLoanScheme([&](const std::pair<std::string, uint64_t>& key, const CLoanSchemeMessage&)
     {
-        if (key.first == loanSchemeID) {
+        if (key.first == loanSchemeID)
             loanUpdateHeights.push_back(key.second);
-        }
         return true;
     });
 
-    for (const auto& height : loanUpdateHeights) {
+    for (const auto& height : loanUpdateHeights)
         EraseDelayedLoanScheme(loanSchemeID, height);
-    }
 
     // Delete loan scheme
     EraseBy<LoanSchemeKey>(loanSchemeID);
@@ -195,95 +193,165 @@ void CLoanView::EraseDelayedDestroyScheme(const std::string& loanSchemeID)
     EraseBy<DestroyLoanSchemeKey>(loanSchemeID);
 }
 
-boost::optional<CInterestRate> CLoanView::GetInterestRate(const CVaultId& vaultId, DCT_ID id)
+boost::optional<CInterestRateV2> CLoanView::GetInterestRate(const CVaultId& vaultId, DCT_ID id, uint32_t height)
 {
-    return ReadBy<LoanInterestByVault, CInterestRate>(std::make_pair(vaultId, id));
+    if (height >= Params().GetConsensus().FortCanningHillHeight)
+        return ReadBy<LoanInterestV2ByVault, CInterestRateV2>(std::make_pair(vaultId, id));
+
+    if (auto rate = ReadBy<LoanInterestByVault, CInterestRate>(std::make_pair(vaultId, id)))
+        return ConvertInterestRateToV2(*rate);
+
+    return {};
 }
 
-inline CAmount InterestPerBlock(CAmount amount, CAmount tokenInterest, CAmount schemeInterest)
+// precision COIN
+template<typename T>
+inline T InterestPerBlockCalculationV1(CAmount amount, CAmount tokenInterest, CAmount schemeInterest)
 {
     auto netInterest = (tokenInterest + schemeInterest) / 100; // in %
-    return MultiplyAmounts(netInterest, amount) / (365 * Params().GetConsensus().blocksPerDay());
+    static const auto blocksPerYear = T(365) * Params().GetConsensus().blocksPerDay();
+    return MultiplyAmounts(netInterest, amount) / blocksPerYear;
 }
 
-inline float InterestPerBlockFloat(CAmount amount, CAmount tokenInterest, CAmount schemeInterest)
+// precisoin COIN ^3
+inline base_uint<128> InterestPerBlockCalculationV2(CAmount amount, CAmount tokenInterest, CAmount schemeInterest)
 {
     auto netInterest = (tokenInterest + schemeInterest) / 100; // in %
-    return MultiplyAmounts(netInterest, amount) / (365.f * Params().GetConsensus().blocksPerDay());
+    static const auto blocksPerYear = 365 * Params().GetConsensus().blocksPerDay();
+    return arith_uint256(amount) * netInterest * COIN / blocksPerYear;
 }
 
-CAmount TotalInterest(const CInterestRate& rate, uint32_t height)
+static base_uint<128> InterestPerBlockCalculation(CAmount amount, CAmount tokenInterest, CAmount schemeInterest, uint32_t height)
 {
-    CAmount interest = rate.interestToHeight + ((height - rate.height) * rate.interestPerBlock);
+    if (int(height) >= Params().GetConsensus().FortCanningHillHeight)
+        return InterestPerBlockCalculationV2(amount, tokenInterest, schemeInterest);
+
+    if (int(height) >= Params().GetConsensus().FortCanningMuseumHeight)
+        return std::ceil(InterestPerBlockCalculationV1<float>(amount, tokenInterest, schemeInterest));
+
+    return InterestPerBlockCalculationV1<CAmount>(amount, tokenInterest, schemeInterest);
+}
+
+CAmount CeilInterest(const base_uint<128>& value, uint32_t height)
+{
+    if (int(height) >= Params().GetConsensus().FortCanningHillHeight) {
+        CAmount amount = (value / base_uint<128>(HIGH_PRECISION_SCALER)).GetLow64();
+        amount += CAmount(value != base_uint<128>(amount) * HIGH_PRECISION_SCALER);
+        return amount;
+    }
+    return value.GetLow64();
+}
 
-    LogPrint(BCLog::LOAN, "%s(): CInterestRate{.height=%d, .perBlock=%d, .toHeight=%d}, height %d - totalInterest %d\n", __func__, rate.height, rate.interestPerBlock, rate.interestToHeight, height, interest);
+base_uint<128> TotalInterestCalculation(const CInterestRateV2& rate, uint32_t height)
+{
+    auto interest = rate.interestToHeight + ((height - rate.height) * rate.interestPerBlock);
+
+    LogPrint(BCLog::LOAN, "%s(): CInterestRate{.height=%d, .perBlock=%d, .toHeight=%d}, height %d - totalInterest %d\n", __func__, rate.height, InterestPerBlock(rate, height), CeilInterest(rate.interestToHeight, height), height, CeilInterest(interest, height));
     return interest;
 }
 
+static base_uint<128> ToHigherPrecision(CAmount amount, uint32_t height)
+{
+    base_uint<128> amountHP = amount;
+    if (int(height) >= Params().GetConsensus().FortCanningHillHeight)
+        amountHP *= HIGH_PRECISION_SCALER;
+
+    return amountHP;
+}
+
+CAmount TotalInterest(const CInterestRateV2& rate, uint32_t height)
+{
+    return CeilInterest(TotalInterestCalculation(rate, height), height);
+}
+
+CAmount InterestPerBlock(const CInterestRateV2& rate, uint32_t height)
+{
+    return CeilInterest(rate.interestPerBlock, height);
+}
+
+void CLoanView::WriteInterestRate(const std::pair<CVaultId, DCT_ID>& pair, const CInterestRateV2& rate, uint32_t height)
+{
+    if (height >= Params().GetConsensus().FortCanningHillHeight)
+        WriteBy<LoanInterestV2ByVault>(pair, rate);
+    else
+        WriteBy<LoanInterestByVault>(pair, ConvertInterestRateToV1(rate));
+}
+
 Res CLoanView::StoreInterest(uint32_t height, const CVaultId& vaultId, const std::string& loanSchemeID, DCT_ID id, CAmount loanIncreased)
 {
     auto scheme = GetLoanScheme(loanSchemeID);
-    if (!scheme) {
+    if (!scheme)
         return Res::Err("No such scheme id %s", loanSchemeID);
-    }
+
     auto token = GetLoanTokenByID(id);
-    if (!token) {
+    if (!token)
         return Res::Err("No such loan token id %s", id.ToString());
-    }
 
-    CInterestRate rate{};
-    ReadBy<LoanInterestByVault>(std::make_pair(vaultId, id), rate);
+    CInterestRateV2 rate{};
+    if (auto readRate = GetInterestRate(vaultId, id, height))
+        rate = *readRate;
 
-    if (rate.height > height || height == 0) {
+    if (rate.height > height || height == 0)
         return Res::Err("Cannot store height in the past");
-    }
+
     if (rate.height) {
         LogPrint(BCLog::LOAN,"%s():\n", __func__);
-        rate.interestToHeight = TotalInterest(rate, height);
+        rate.interestToHeight = TotalInterestCalculation(rate, height);
     }
 
-    if (int(height) >= Params().GetConsensus().FortCanningMuseumHeight) {
-        rate.interestPerBlock += std::ceil(InterestPerBlockFloat(loanIncreased, token->interest, scheme->rate));
-    } else {
-        rate.interestPerBlock += InterestPerBlock(loanIncreased, token->interest, scheme->rate);
-    }
+    if (int(height) >= Params().GetConsensus().FortCanningHillHeight) {
+        CBalances amounts;
+        ReadBy<LoanTokenAmount>(vaultId, amounts);
+        rate.interestPerBlock = InterestPerBlockCalculation(amounts.balances[id], token->interest, scheme->rate, height);
+    } else
+        rate.interestPerBlock += InterestPerBlockCalculation(loanIncreased, token->interest, scheme->rate, height);
+
     rate.height = height;
 
-    WriteBy<LoanInterestByVault>(std::make_pair(vaultId, id), rate);
+    WriteInterestRate(std::make_pair(vaultId, id), rate, height);
     return Res::Ok();
 }
 
 Res CLoanView::EraseInterest(uint32_t height, const CVaultId& vaultId, const std::string& loanSchemeID, DCT_ID id, CAmount loanDecreased, CAmount interestDecreased)
 {
     auto scheme = GetLoanScheme(loanSchemeID);
-    if (!scheme) {
+    if (!scheme)
         return Res::Err("No such scheme id %s", loanSchemeID);
-    }
+
     auto token = GetLoanTokenByID(id);
-    if (!token) {
+    if (!token)
         return Res::Err("No such loan token id %s", id.ToString());
-    }
 
-    CInterestRate rate{};
-    ReadBy<LoanInterestByVault>(std::make_pair(vaultId, id), rate);
+    CInterestRateV2 rate{};
+    if (auto readRate = GetInterestRate(vaultId, id, height))
+        rate = *readRate;
 
-    if (rate.height > height) {
+    if (rate.height > height)
         return Res::Err("Cannot store height in the past");
-    }
-    if (rate.height == 0) {
+
+    if (rate.height == 0)
         return Res::Err("Data mismatch height == 0");
-    }
+
+    auto interestDecreasedHP = ToHigherPrecision(interestDecreased, height);
+
     LogPrint(BCLog::LOAN,"%s():\n", __func__);
-    rate.interestToHeight = std::max(CAmount{0}, TotalInterest(rate, height) - interestDecreased);
+    auto interestToHeight = TotalInterestCalculation(rate, height);
+    rate.interestToHeight = interestToHeight < interestDecreasedHP ? 0
+                          : interestToHeight - interestDecreasedHP;
 
     rate.height = height;
-    if (int(height) >= Params().GetConsensus().FortCanningMuseumHeight) {
-        rate.interestPerBlock = std::max(CAmount{0}, rate.interestPerBlock - CAmount(std::ceil(InterestPerBlockFloat(loanDecreased, token->interest, scheme->rate))));
+
+    if (int(height) >= Params().GetConsensus().FortCanningHillHeight) {
+        CBalances amounts;
+        ReadBy<LoanTokenAmount>(vaultId, amounts);
+        rate.interestPerBlock = InterestPerBlockCalculation(amounts.balances[id], token->interest, scheme->rate, height);
     } else {
-        rate.interestPerBlock = std::max(CAmount{0}, rate.interestPerBlock - InterestPerBlock(loanDecreased, token->interest, scheme->rate));
+        auto interestPerBlock = InterestPerBlockCalculation(loanDecreased, token->interest, scheme->rate, height);
+        rate.interestPerBlock = rate.interestPerBlock < interestPerBlock ? 0
+                              : rate.interestPerBlock - interestPerBlock;
     }
 
-    WriteBy<LoanInterestByVault>(std::make_pair(vaultId, id), rate);
+    WriteInterestRate(std::make_pair(vaultId, id), rate, height);
     return Res::Ok();
 }
 
@@ -294,52 +362,95 @@ void CLoanView::ForEachVaultInterest(std::function<bool(const CVaultId&, DCT_ID,
     }, std::make_pair(vaultId, id));
 }
 
-Res CLoanView::DeleteInterest(const CVaultId& vaultId)
+void CLoanView::ForEachVaultInterestV2(std::function<bool(const CVaultId&, DCT_ID, CInterestRateV2)> callback, const CVaultId& vaultId, DCT_ID id)
+{
+    ForEach<LoanInterestV2ByVault, std::pair<CVaultId, DCT_ID>, CInterestRateV2>([&](const std::pair<CVaultId, DCT_ID>& pair, CInterestRateV2 rate) {
+        return callback(pair.first, pair.second, rate);
+    }, std::make_pair(vaultId, id));
+}
+
+template<typename BoundType>
+void DeleteInterest(CLoanView& view, const CVaultId& vaultId)
 {
     std::vector<std::pair<CVaultId, DCT_ID>> keysToDelete;
 
-    auto it = LowerBound<LoanInterestByVault>(std::make_pair(vaultId, DCT_ID{0}));
-    for (; it.Valid() && it.Key().first == vaultId; it.Next()) {
+    auto it = view.LowerBound<BoundType>(std::make_pair(vaultId, DCT_ID{0}));
+    for (; it.Valid() && it.Key().first == vaultId; it.Next())
         keysToDelete.push_back(it.Key());
-    }
 
-    for (const auto& key : keysToDelete) {
-        EraseBy<LoanInterestByVault>(key);
-    }
+    for (const auto& key : keysToDelete)
+        view.EraseBy<BoundType>(key);
+}
+
+Res CLoanView::DeleteInterest(const CVaultId& vaultId, uint32_t height)
+{
+    if (height >= Params().GetConsensus().FortCanningHillHeight)
+        ::DeleteInterest<LoanInterestV2ByVault>(*this, vaultId);
+    else
+        ::DeleteInterest<LoanInterestByVault>(*this, vaultId);
+
     return Res::Ok();
 }
 
+void CLoanView::RevertInterestRateToV1()
+{
+    std::vector<std::pair<CVaultId, DCT_ID>> pairs;
+
+    ForEach<LoanInterestV2ByVault, std::pair<CVaultId, DCT_ID>, CInterestRateV2>([&](const std::pair<CVaultId, DCT_ID>& pair, CLazySerialize<CInterestRateV2>) {
+        pairs.emplace_back(pair);
+        return true;
+    });
+
+    for (auto it = pairs.begin(); it != pairs.end(); it = pairs.erase(it)) {
+        EraseBy<LoanInterestV2ByVault>(*it);
+    }
+}
+
+void CLoanView::MigrateInterestRateToV2(CVaultView &view, uint32_t height)
+{
+    ForEachVaultInterest([&](const CVaultId& vaultId, DCT_ID tokenId, CInterestRate rate) {
+        auto newRate = ConvertInterestRateToV2(rate);
+        newRate.interestPerBlock *= HIGH_PRECISION_SCALER;
+        newRate.interestToHeight *= HIGH_PRECISION_SCALER;
+        WriteBy<LoanInterestV2ByVault>(std::make_pair(vaultId, tokenId), newRate);
+
+        const auto vault = view.GetVault(vaultId);
+        StoreInterest(height, vaultId, vault->schemeId, tokenId, 0);
+        return true;
+    });
+}
+
 Res CLoanView::AddLoanToken(const CVaultId& vaultId, CTokenAmount amount)
 {
-    if (!GetLoanTokenByID(amount.nTokenId)) {
+    if (!GetLoanTokenByID(amount.nTokenId))
         return Res::Err("No such loan token id %s", amount.nTokenId.ToString());
-    }
+
     CBalances amounts;
     ReadBy<LoanTokenAmount>(vaultId, amounts);
     auto res = amounts.Add(amount);
-    if (!res) {
+    if (!res)
         return res;
-    }
-    if (!amounts.balances.empty()) {
+
+    if (!amounts.balances.empty())
         WriteBy<LoanTokenAmount>(vaultId, amounts);
-    }
+
     return Res::Ok();
 }
 
 Res CLoanView::SubLoanToken(const CVaultId& vaultId, CTokenAmount amount)
 {
-    if (!GetLoanTokenByID(amount.nTokenId)) {
+    if (!GetLoanTokenByID(amount.nTokenId))
         return Res::Err("No such loan token id %s", amount.nTokenId.ToString());
-    }
+
     auto amounts = GetLoanTokens(vaultId);
-    if (!amounts || !amounts->Sub(amount)) {
+    if (!amounts || !amounts->Sub(amount))
         return Res::Err("Loan token for vault <%s> not found", vaultId.GetHex());
-    }
-    if (amounts->balances.empty()) {
+
+    if (amounts->balances.empty())
         EraseBy<LoanTokenAmount>(vaultId);
-    } else {
+    else
         WriteBy<LoanTokenAmount>(vaultId, *amounts);
-    }
+
     return Res::Ok();
 }
 
@@ -362,8 +473,8 @@ Res CLoanView::SetLoanLiquidationPenalty(CAmount penalty)
 CAmount CLoanView::GetLoanLiquidationPenalty()
 {
     CAmount penalty;
-    if (Read(LoanLiquidationPenalty::prefix(), penalty)) {
+    if (Read(LoanLiquidationPenalty::prefix(), penalty))
         return penalty;
-    }
+
     return 5 * COIN / 100;
 }
diff --git a/src/masternodes/loan.h b/src/masternodes/loan.h
index 8a114c6936..33cb7cfdb8 100644
--- a/src/masternodes/loan.h
+++ b/src/masternodes/loan.h
@@ -223,7 +223,48 @@ struct CInterestRate
     }
 };
 
-CAmount TotalInterest(const CInterestRate& rate, uint32_t height);
+struct CInterestRateV2
+{
+    uint32_t height;
+    base_uint<128> interestPerBlock;
+    base_uint<128> interestToHeight;
+
+    ADD_SERIALIZE_METHODS;
+
+    template <typename Stream, typename Operation>
+    inline void SerializationOp(Stream& s, Operation ser_action) {
+        READWRITE(height);
+        READWRITE(interestPerBlock);
+        READWRITE(interestToHeight);
+    }
+};
+
+inline CInterestRate ConvertInterestRateToV1(const CInterestRateV2& rate1)
+{
+    CInterestRate rate2{};
+    rate2.height = rate1.height;
+    rate2.interestPerBlock = rate1.interestPerBlock.GetLow64();
+    rate2.interestToHeight = rate1.interestToHeight.GetLow64();
+
+    return rate2;
+}
+
+inline CInterestRateV2 ConvertInterestRateToV2(const CInterestRate& rate1)
+{
+    CInterestRateV2 rate2{};
+    rate2.height = rate1.height;
+    rate2.interestPerBlock = rate1.interestPerBlock;
+    rate2.interestToHeight = rate1.interestToHeight;
+
+    return rate2;
+}
+
+static const CAmount HIGH_PRECISION_SCALER = COIN * COIN; // 1,0000,0000,0000,0000
+
+CAmount TotalInterest(const CInterestRateV2& rate, uint32_t height);
+CAmount InterestPerBlock(const CInterestRateV2& rate, uint32_t height);
+base_uint<128> TotalInterestCalculation(const CInterestRateV2& rate, uint32_t height);
+CAmount CeilInterest(const base_uint<128>& value, uint32_t height);
 
 class CLoanTakeLoanMessage
 {
@@ -290,11 +331,15 @@ class CLoanView : public virtual CStorageView {
     void ForEachDelayedLoanScheme(std::function<bool (const std::pair<std::string, uint64_t>&, const CLoanSchemeMessage&)> callback);
     void ForEachDelayedDestroyScheme(std::function<bool (const std::string&, const uint64_t&)> callback);
 
-    Res DeleteInterest(const CVaultId& vaultId);
-    boost::optional<CInterestRate> GetInterestRate(const CVaultId& loanSchemeID, DCT_ID id);
+    Res DeleteInterest(const CVaultId& vaultId, uint32_t height);
+    boost::optional<CInterestRateV2> GetInterestRate(const CVaultId& loanSchemeID, DCT_ID id, uint32_t height);
+    void WriteInterestRate(const std::pair<CVaultId, DCT_ID>& pair, const CInterestRateV2& rate, uint32_t height);
     Res StoreInterest(uint32_t height, const CVaultId& vaultId, const std::string& loanSchemeID, DCT_ID id, CAmount loanIncreased);
     Res EraseInterest(uint32_t height, const CVaultId& vaultId, const std::string& loanSchemeID, DCT_ID id, CAmount loanDecreased, CAmount interestDecreased);
     void ForEachVaultInterest(std::function<bool(const CVaultId&, DCT_ID, CInterestRate)> callback, const CVaultId& vaultId = uint256(), DCT_ID id = {0});
+    void ForEachVaultInterestV2(std::function<bool(const CVaultId&, DCT_ID, CInterestRateV2)> callback, const CVaultId& vaultId = uint256(), DCT_ID id = {0});
+    void RevertInterestRateToV1();
+    void MigrateInterestRateToV2(CVaultView &view, uint32_t height);
 
     Res AddLoanToken(const CVaultId& vaultId, CTokenAmount amount);
     Res SubLoanToken(const CVaultId& vaultId, CTokenAmount amount);
@@ -315,6 +360,7 @@ class CLoanView : public virtual CStorageView {
     struct LoanInterestByVault              { static constexpr uint8_t prefix() { return 0x18; } };
     struct LoanTokenAmount                  { static constexpr uint8_t prefix() { return 0x19; } };
     struct LoanLiquidationPenalty           { static constexpr uint8_t prefix() { return 0x1A; } };
+    struct LoanInterestV2ByVault            { static constexpr uint8_t prefix() { return 0x1B; } };
 };
 
 #endif // DEFI_MASTERNODES_LOAN_H
diff --git a/src/masternodes/masternodes.cpp b/src/masternodes/masternodes.cpp
index 811d811f93..86b528af9c 100644
--- a/src/masternodes/masternodes.cpp
+++ b/src/masternodes/masternodes.cpp
@@ -950,7 +950,7 @@ ResVal<CCollateralLoans> CCustomCSView::GetLoanCollaterals(CVaultId const& vault
     if (!res)
         return std::move(res);
 
-    LogPrint(BCLog::LOAN, "\t\t%s(): totalCollaterals - %lld, totalLoans - %lld, ratio - %d\n",  
+    LogPrint(BCLog::LOAN, "\t\t%s(): totalCollaterals - %lld, totalLoans - %lld, ratio - %d\n",
         __func__, result.totalCollaterals, result.totalLoans, result.ratio());
 
     return ResVal<CCollateralLoans>(result, Res::Ok());
@@ -993,7 +993,7 @@ Res CCustomCSView::PopulateLoansData(CCollateralLoans& result, CVaultId const& v
         if (!token)
             return Res::Err("Loan token with id (%s) does not exist!", loanTokenId.ToString());
 
-        auto rate = GetInterestRate(vaultId, loanTokenId);
+        auto rate = GetInterestRate(vaultId, loanTokenId, height);
         if (!rate)
             return Res::Err("Cannot get interest rate for token (%s)!", token->symbol);
 
diff --git a/src/masternodes/masternodes.h b/src/masternodes/masternodes.h
index cd30b183cc..178dd48604 100644
--- a/src/masternodes/masternodes.h
+++ b/src/masternodes/masternodes.h
@@ -380,7 +380,7 @@ class CCustomCSView
                                         ICXOrderStatus, ICXOfferStatus, ICXSubmitDFCHTLCStatus, ICXSubmitEXTHTLCStatus, ICXVariables,
             CLoanView               ::  LoanSetCollateralTokenCreationTx, LoanSetCollateralTokenKey, LoanSetLoanTokenCreationTx,
                                         LoanSetLoanTokenKey, LoanSchemeKey, DefaultLoanSchemeKey, DelayedLoanSchemeKey,
-                                        DestroyLoanSchemeKey, LoanInterestByVault, LoanTokenAmount, LoanLiquidationPenalty,
+                                        DestroyLoanSchemeKey, LoanInterestByVault, LoanTokenAmount, LoanLiquidationPenalty, LoanInterestV2ByVault,
             CVaultView              ::  VaultKey, OwnerVaultKey, CollateralKey, AuctionBatchKey, AuctionHeightKey, AuctionBidKey
         >();
     }
diff --git a/src/masternodes/mn_checks.cpp b/src/masternodes/mn_checks.cpp
index fb137d725d..732d87c6bb 100644
--- a/src/masternodes/mn_checks.cpp
+++ b/src/masternodes/mn_checks.cpp
@@ -2533,7 +2533,7 @@ class CCustomTxApplyVisitor : public CCustomTxVisitor
         }
 
         // delete all interest to vault
-        res = mnview.DeleteInterest(obj.vaultId);
+        res = mnview.DeleteInterest(obj.vaultId, height);
         if (!res)
             return res;
 
@@ -2840,7 +2840,7 @@ class CCustomTxApplyVisitor : public CCustomTxVisitor
             if (it == loanAmounts->balances.end())
                 return Res::Err("There is no loan on token (%s) in this vault!", loanToken->symbol);
 
-            auto rate = mnview.GetInterestRate(obj.vaultId, tokenId);
+            auto rate = mnview.GetInterestRate(obj.vaultId, tokenId, height);
             if (!rate)
                 return Res::Err("Cannot get interest rate for this token (%s)!", loanToken->symbol);
 
@@ -2867,12 +2867,12 @@ class CCustomTxApplyVisitor : public CCustomTxVisitor
 
             if (static_cast<int>(height) >= consensus.FortCanningMuseumHeight && subLoan < it->second)
             {
-                auto newRate = mnview.GetInterestRate(obj.vaultId, tokenId);
+                auto newRate = mnview.GetInterestRate(obj.vaultId, tokenId, height);
                 if (!newRate)
                     return Res::Err("Cannot get interest rate for this token (%s)!", loanToken->symbol);
 
                 if (newRate->interestPerBlock == 0)
-                        return Res::Err("Cannot payback this amount of loan for %s, either payback full amount or less than this amount!", loanToken->symbol);
+                    return Res::Err("Cannot payback this amount of loan for %s, either payback full amount or less than this amount!", loanToken->symbol);
             }
 
             res = mnview.SubMintedTokens(loanToken->creationTx, subLoan);
@@ -3213,6 +3213,19 @@ Res CustomMetadataParse(uint32_t height, const Consensus::Params& consensus, con
 }
 
 Res CustomTxVisit(CCustomCSView& mnview, const CCoinsViewCache& coins, const CTransaction& tx, uint32_t height, const Consensus::Params& consensus, const CCustomTxMessage& txMessage, uint64_t time) {
+    if (height == Params().GetConsensus().FortCanningHillHeight -1 || height == Params().GetConsensus().FortCanningHillHeight)
+    {
+        TBytes dummy;
+        switch(GuessCustomTxType(tx, dummy))
+        {
+            case CustomTxType::TakeLoan: case CustomTxType::PaybackLoan: case CustomTxType::DepositToVault:
+            case CustomTxType::WithdrawFromVault: case CustomTxType::UpdateVault:
+                return Res::Err("This type of transaction is not possible around hard fork height");
+                break;
+            default:
+                break;
+        }
+    }
     try {
         return boost::apply_visitor(CCustomTxApplyVisitor(tx, height, coins, mnview, consensus, time), txMessage);
     } catch (const std::exception& e) {
diff --git a/src/masternodes/mn_rpc.cpp b/src/masternodes/mn_rpc.cpp
index 1e2643c185..eb7d028021 100644
--- a/src/masternodes/mn_rpc.cpp
+++ b/src/masternodes/mn_rpc.cpp
@@ -443,6 +443,12 @@ void execTestTx(const CTransaction& tx, uint32_t height, CTransactionRef optAuth
     }
 }
 
+void RPCCheckFortCanningHillConstraint(int height)
+{
+    if (height == Params().GetConsensus().FortCanningHillHeight -1 || height == Params().GetConsensus().FortCanningHillHeight)
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "This type of transaction is not possible around hard fork height");
+}
+
 CWalletCoinsUnlocker GetWallet(const JSONRPCRequest& request) {
     auto wallet = GetWalletForJSONRPCRequest(request);
 
diff --git a/src/masternodes/mn_rpc.h b/src/masternodes/mn_rpc.h
index 96952525b0..d3396b11ec 100644
--- a/src/masternodes/mn_rpc.h
+++ b/src/masternodes/mn_rpc.h
@@ -59,5 +59,6 @@ CAccounts SelectAccountsByTargetBalances(const CAccounts& accounts, const CBalan
 void execTestTx(const CTransaction& tx, uint32_t height, CTransactionRef optAuthTx = {});
 CScript CreateScriptForHTLC(const JSONRPCRequest& request, uint32_t &blocks, std::vector<unsigned char>& image);
 CPubKey PublickeyFromString(const std::string &pubkey);
+void RPCCheckFortCanningHillConstraint(int height);
 
 #endif // DEFI_MASTERNODES_MN_RPC_H
diff --git a/src/masternodes/rpc_loan.cpp b/src/masternodes/rpc_loan.cpp
index 0e86251a45..535311f13f 100644
--- a/src/masternodes/rpc_loan.cpp
+++ b/src/masternodes/rpc_loan.cpp
@@ -1266,8 +1266,9 @@ UniValue getloaninfo(const JSONRPCRequest& request) {
 
     LOCK(cs_main);
 
-
     auto height = ::ChainActive().Height() + 1;
+    RPCCheckFortCanningHillConstraint(height);
+
     bool useNextPrice = false, requireLivePrice = true;
     auto lastBlockTime = ::ChainActive().Tip()->GetBlockTime();
     uint64_t totalCollateralValue = 0, totalLoanValue = 0, totalVaults = 0, totalAuctions = 0;
@@ -1362,10 +1363,12 @@ UniValue getinterest(const JSONRPCRequest& request) {
     UniValue ret(UniValue::VARR);
     uint32_t height = ::ChainActive().Height() + 1;
 
-    std::map<DCT_ID, std::pair<CAmount, CAmount> > interest;
+    RPCCheckFortCanningHillConstraint(height);
+
+    std::map<DCT_ID, std::pair<base_uint<128>, base_uint<128>> > interest;
 
     LogPrint(BCLog::LOAN,"%s():\n", __func__);
-    pcustomcsview->ForEachVaultInterest([&](const CVaultId& vaultId, DCT_ID tokenId, CInterestRate rate)
+    auto vaultInterest = [&](const CVaultId& vaultId, DCT_ID tokenId, CInterestRateV2 rate)
     {
         auto vault = pcustomcsview->GetVault(vaultId);
         if (!vault || vault->schemeId != loanSchemeId)
@@ -1378,19 +1381,32 @@ UniValue getinterest(const JSONRPCRequest& request) {
             return true;
 
         LogPrint(BCLog::LOAN,"\t\tVault(%s)->", vaultId.GetHex()); /* Continued */
-        interest[tokenId].first += TotalInterest(rate, height);
+        interest[tokenId].first += TotalInterestCalculation(rate, height);
         interest[tokenId].second += rate.interestPerBlock;
 
         return true;
-    });
+    };
+
+    if (height >= Params().GetConsensus().FortCanningHillHeight) {
+        pcustomcsview->ForEachVaultInterestV2(vaultInterest);
+    } else {
+        pcustomcsview->ForEachVaultInterest([&](const CVaultId& vaultId, DCT_ID tokenId, CInterestRate rate) {
+            return vaultInterest(vaultId, tokenId, ConvertInterestRateToV2(rate));
+        });
+    }
 
     UniValue obj(UniValue::VOBJ);
-    for (std::map<DCT_ID, std::pair<CAmount, CAmount> >::iterator it=interest.begin(); it!=interest.end(); ++it)
+    for (std::map<DCT_ID, std::pair<base_uint<128>, base_uint<128> > >::iterator it=interest.begin(); it!=interest.end(); ++it)
     {
         auto token = pcustomcsview->GetToken(it->first);
         obj.pushKV("token", token->CreateSymbolKey(it->first));
-        obj.pushKV("totalInterest", ValueFromAmount(it->second.first));
-        obj.pushKV("interestPerBlock", ValueFromAmount(it->second.second));
+        obj.pushKV("totalInterest", ValueFromAmount(CeilInterest(it->second.first, height)));
+        obj.pushKV("interestPerBlock", ValueFromAmount(CeilInterest(it->second.second, height)));
+        if (height >= Params().GetConsensus().FortCanningHillHeight)
+        {
+            auto subSatoshiInterest = (it->second.second - ((it->second.second / HIGH_PRECISION_SCALER) * HIGH_PRECISION_SCALER)).GetLow64();
+            obj.pushKV("immatureInterest", UniValue(UniValue::VNUM, strprintf("0.%de-8", subSatoshiInterest)));
+        }
 
         ret.push_back(obj);
     }
diff --git a/src/masternodes/rpc_vault.cpp b/src/masternodes/rpc_vault.cpp
index 7555056054..4554a710cd 100644
--- a/src/masternodes/rpc_vault.cpp
+++ b/src/masternodes/rpc_vault.cpp
@@ -43,6 +43,8 @@ namespace {
 
     bool WillLiquidateNext(const CVaultId& vaultId, const CVaultData& vault) {
         auto height = ::ChainActive().Height();
+        RPCCheckFortCanningHillConstraint(height);
+
         auto blockTime = ::ChainActive()[height]->GetBlockTime();
 
         auto collaterals = pcustomcsview->GetVaultCollaterals(vaultId);
@@ -152,7 +154,7 @@ namespace {
             for (const auto& loan : loanTokens->balances) {
                 auto token = pcustomcsview->GetLoanTokenByID(loan.first);
                 if (!token) continue;
-                auto rate = pcustomcsview->GetInterestRate(vaultId, loan.first);
+                auto rate = pcustomcsview->GetInterestRate(vaultId, loan.first, height);
                 if (!rate) continue;
                 LogPrint(BCLog::LOAN,"%s()->%s->", __func__, token->symbol); /* Continued */
                 auto totalInterest = TotalInterest(*rate, height + 1);
diff --git a/src/test/arith_uint256_tests.cpp b/src/test/arith_uint256_tests.cpp
index 7133572c9d..0b2550d329 100644
--- a/src/test/arith_uint256_tests.cpp
+++ b/src/test/arith_uint256_tests.cpp
@@ -119,6 +119,8 @@ BOOST_AUTO_TEST_CASE( basics ) // constructors, equality, inequality
     tmpL = ~R1L; BOOST_CHECK(tmpL == ~R1L);
     tmpL = ~R2L; BOOST_CHECK(tmpL == ~R2L);
     tmpL = ~MaxL; BOOST_CHECK(tmpL == ~MaxL);
+
+    BOOST_CHECK(OneL == base_uint<256>(base_uint<128>(OneL)));
 }
 
 static void shiftArrayRight(unsigned char* to, const unsigned char* from, unsigned int arrayLength, unsigned int bitsToShift)
@@ -336,10 +338,14 @@ BOOST_AUTO_TEST_CASE( multiply )
 
     BOOST_CHECK(MaxL * MaxL == OneL);
 
-    BOOST_CHECK((R1L * 0) == 0);
-    BOOST_CHECK((R1L * 1) == R1L);
-    BOOST_CHECK((R1L * 3).ToString() == "7759b1c0ed14047f961ad09b20ff83687876a0181a367b813634046f91def7d4");
-    BOOST_CHECK((R2L * 0x87654321UL).ToString() == "23f7816e30c4ae2017257b7a0fa64d60402f5234d46e746b61c960d09a26d070");
+    BOOST_CHECK((R1L * 0u) == 0u);
+    BOOST_CHECK((R1L * 1u) == R1L);
+    BOOST_CHECK((R1L * 3u).ToString() == "7759b1c0ed14047f961ad09b20ff83687876a0181a367b813634046f91def7d4");
+    BOOST_CHECK((R2L * 0x87654321).ToString() == "23f7816e30c4ae2017257b7a0fa64d60402f5234d46e746b61c960d09a26d070");
+
+    BOOST_CHECK((R1L * 10000000) == (R1L * arith_uint256(10000000)));
+    BOOST_CHECK((R1L * COIN) == (R1L * arith_uint256(COIN)));
+    BOOST_CHECK((R1L * (COIN * COIN)) == (R1L * arith_uint256(COIN * COIN)));
 }
 
 BOOST_AUTO_TEST_CASE( divide )
diff --git a/src/test/loan_tests.cpp b/src/test/loan_tests.cpp
index 80f3d2cb30..2bd1581ee6 100644
--- a/src/test/loan_tests.cpp
+++ b/src/test/loan_tests.cpp
@@ -91,32 +91,32 @@ BOOST_AUTO_TEST_CASE(loan_iterest_rate)
     auto vault_id = NextTx();
     BOOST_REQUIRE(mnview.StoreInterest(1, vault_id, id, token_id, 1 * COIN));
 
-    auto rate = mnview.GetInterestRate(vault_id, token_id);
+    auto rate = mnview.GetInterestRate(vault_id, token_id, 1);
     BOOST_REQUIRE(rate);
-    BOOST_CHECK_EQUAL(rate->interestToHeight, 0);
+    BOOST_CHECK_EQUAL(rate->interestToHeight.GetLow64(), 0);
     BOOST_CHECK_EQUAL(rate->height, 1);
 
     auto interestPerBlock = rate->interestPerBlock;
     BOOST_REQUIRE(mnview.StoreInterest(5, vault_id, id, token_id, 1 * COIN));
 
-    rate = mnview.GetInterestRate(vault_id, token_id);
+    rate = mnview.GetInterestRate(vault_id, token_id, 5);
     BOOST_REQUIRE(rate);
     BOOST_CHECK_EQUAL(rate->height, 5);
-    BOOST_CHECK_EQUAL(rate->interestToHeight, 4 * interestPerBlock);
+    BOOST_CHECK_EQUAL(rate->interestToHeight.GetLow64(), 4 * interestPerBlock.GetLow64());
 
     auto interestToHeight = rate->interestToHeight;
     interestPerBlock = rate->interestPerBlock;
-    BOOST_REQUIRE(mnview.EraseInterest(6, vault_id, id, token_id, 1 * COIN, interestToHeight + interestPerBlock));
-    rate = mnview.GetInterestRate(vault_id, token_id);
+    BOOST_REQUIRE(mnview.EraseInterest(6, vault_id, id, token_id, 1 * COIN, (interestToHeight + interestPerBlock).GetLow64()));
+    rate = mnview.GetInterestRate(vault_id, token_id, 6);
 
     BOOST_REQUIRE(rate);
-    BOOST_CHECK_EQUAL(rate->interestToHeight, 0);
+    BOOST_CHECK_EQUAL(rate->interestToHeight.GetLow64(), 0);
 
     BOOST_REQUIRE(mnview.EraseInterest(6, vault_id, id, token_id, 1 * COIN, 0));
 
-    rate = mnview.GetInterestRate(vault_id, token_id);
+    rate = mnview.GetInterestRate(vault_id, token_id, 6);
     BOOST_REQUIRE(rate);
-    BOOST_CHECK_EQUAL(rate->interestToHeight, 0);
+    BOOST_CHECK_EQUAL(rate->interestToHeight.GetLow64(), 0);
 }
 
 BOOST_AUTO_TEST_CASE(collateralization_ratio)
diff --git a/src/uint256.cpp b/src/uint256.cpp
index 22cdf66ecb..688364e907 100644
--- a/src/uint256.cpp
+++ b/src/uint256.cpp
@@ -63,16 +63,11 @@ std::string base_blob<BITS>::ToString() const
     return (GetHex());
 }
 
+// Explicit instantiations for base_blob<128>
+template class base_blob<128>;
+
 // Explicit instantiations for base_blob<160>
-template base_blob<160>::base_blob(const std::vector<unsigned char>&);
-template std::string base_blob<160>::GetHex() const;
-template std::string base_blob<160>::ToString() const;
-template void base_blob<160>::SetHex(const char*);
-template void base_blob<160>::SetHex(const std::string&);
+template class base_blob<160>;
 
 // Explicit instantiations for base_blob<256>
-template base_blob<256>::base_blob(const std::vector<unsigned char>&);
-template std::string base_blob<256>::GetHex() const;
-template std::string base_blob<256>::ToString() const;
-template void base_blob<256>::SetHex(const char*);
-template void base_blob<256>::SetHex(const std::string&);
+template class base_blob<256>;
diff --git a/src/validation.cpp b/src/validation.cpp
index ae95ae73b8..87fbdad52b 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -1790,6 +1790,14 @@ DisconnectResult CChainState::DisconnectBlock(const CBlock& block, const CBlockI
         }
     }
 
+    // one time downgrade to revert CInterestRateV2 structure
+    if (pindex->nHeight == Params().GetConsensus().FortCanningHillHeight) {
+        auto time = GetTimeMillis();
+        LogPrintf("Interest rate reverting ...\n");
+        mnview.RevertInterestRateToV1();
+        LogPrint(BCLog::BENCH, "    - Interest rate reverting took: %dms\n", GetTimeMillis() - time);
+    }
+
     // Remove burn balance transfers
     if (pindex->nHeight == Params().GetConsensus().EunosHeight)
     {
@@ -2307,6 +2315,15 @@ bool CChainState::ConnectBlock(const CBlock& block, CValidationState& state, CBl
         return true;
     }
 
+    // one time upgrade to convert the old CInterestRate data structure
+    // we don't neeed it in undos
+    if (pindex->nHeight == chainparams.GetConsensus().FortCanningHillHeight) {
+        auto time = GetTimeMillis();
+        LogPrintf("Interest rate migration ...\n");
+        mnview.MigrateInterestRateToV2(mnview,(uint32_t)pindex->nHeight);
+        LogPrint(BCLog::BENCH, "    - Interest rate migration took: %dms\n", GetTimeMillis() - time);
+    }
+
     CKeyID minterKey;
     boost::optional<uint256> nodeId;
     boost::optional<CMasternode> nodePtr;
@@ -2878,6 +2895,15 @@ bool CChainState::ConnectBlock(const CBlock& block, CValidationState& state, CBl
             LogPrintf("Pruning undo data finished.\n");
             LogPrint(BCLog::BENCH, "    - Pruning undo data takes: %dms\n", GetTimeMillis() - time);
         }
+        // we can safety delete old interest keys
+        if (it->first > chainparams.GetConsensus().FortCanningHillHeight) {
+            CCustomCSView view(mnview);
+            mnview.ForEachVaultInterest([&](const CVaultId& vaultId, DCT_ID tokenId, CInterestRate) {
+                view.EraseBy<CLoanView::LoanInterestByVault>(std::make_pair(vaultId, tokenId));
+                return true;
+            });
+            view.Flush();
+        }
     }
 
     int64_t nTime5 = GetTimeMicros(); nTimeIndex += nTime5 - nTime4;
@@ -3114,13 +3140,13 @@ void CChainState::ProcessLoanEvents(const CBlockIndex* pindex, CCustomCSView& ca
             for (auto& loan : loanTokens->balances) {
                 auto tokenId = loan.first;
                 auto tokenValue = loan.second;
-                auto rate = cache.GetInterestRate(vaultId, tokenId);
+                auto rate = cache.GetInterestRate(vaultId, tokenId, pindex->nHeight);
                 assert(rate);
                 LogPrint(BCLog::LOAN,"\t\t"); /* Continued */
                 auto subInterest = TotalInterest(*rate, pindex->nHeight);
                 totalInterest.Add({tokenId, subInterest});
 
-                // Remove the interests from the vault and the storage respectively  
+                // Remove the interests from the vault and the storage respectively
                 cache.SubLoanToken(vaultId, {tokenId, tokenValue});
                 LogPrint(BCLog::LOAN,"\t\t"); /* Continued */
                 cache.EraseInterest(pindex->nHeight, vaultId, vault->schemeId, tokenId, tokenValue, subInterest);
diff --git a/test/functional/feature_loan_low_interest.py b/test/functional/feature_loan_low_interest.py
new file mode 100755
index 0000000000..681d0c80b9
--- /dev/null
+++ b/test/functional/feature_loan_low_interest.py
@@ -0,0 +1,334 @@
+#!/usr/bin/env python3
+# Copyright (c) 2014-2019 The Bitcoin Core developers
+# Copyright (c) DeFi Blockchain Developers
+# Distributed under the MIT software license, see the accompanying
+# file LICENSE or http://www.opensource.org/licenses/mit-license.php.
+"""Test Loan - interest test."""
+
+from test_framework.test_framework import DefiTestFramework
+
+from test_framework.util import assert_equal
+
+import calendar
+import time
+from decimal import Decimal
+
+FCH_HEIGHT = 1200
+
+class LowInterestTest (DefiTestFramework):
+    def set_test_params(self):
+        self.num_nodes = 1
+        self.setup_clean_chain = True
+        self.extra_args = [
+            ['-txnotokens=0', '-amkheight=1', '-bayfrontheight=1', '-eunosheight=2', '-fortcanningheight=3', '-fortcanningmuseumheight=4', '-fortcanningparkheight=5', f'-fortcanninghillheight={FCH_HEIGHT}', '-jellyfish_regtest=1', '-txindex=1', '-simulatemainnet']
+        ]
+
+    account0 = None
+    oracle_id1 = None
+    symbolDFI = "DFI"
+    symbolDOGE = "DOGE"
+    symboldUSD = "DUSD"
+    idDFI = 0
+    iddUSD = 0
+    idDOGE = 0
+    tokenInterest = 0
+    loanInterest = 0
+
+    def test_load_account0_with_DFI(self):
+        print('loading up account0 with DFI token...')
+        self.nodes[0].generate(100) # get initial UTXO balance from immature to trusted -> check getbalances()
+        self.account0 = self.nodes[0].get_genesis_keys().ownerAuthAddress
+        # UTXO -> token
+        self.nodes[0].utxostoaccount({self.account0: "199999900@" + self.symbolDFI})
+        self.nodes[0].generate(1)
+        account0_balance = self.nodes[0].getaccount(self.account0)
+        assert_equal(account0_balance, ['199999900.00000000@DFI'])
+
+    def test_setup_oracles(self):
+        print('setting up oracles...')
+        oracle_address1 = self.nodes[0].getnewaddress("", "legacy")
+        price_feeds1 = [{"currency": "USD", "token": "DFI"},
+                        {"currency": "USD", "token": "DOGE"}]
+        self.oracle_id1 = self.nodes[0].appointoracle(oracle_address1, price_feeds1, 10)
+        self.nodes[0].generate(1)
+        oracle1_prices = [{"currency": "USD", "tokenAmount": "0.0001@DOGE"},
+                          {"currency": "USD", "tokenAmount": "10@DFI"}]
+        timestamp = calendar.timegm(time.gmtime())
+        self.nodes[0].setoracledata(self.oracle_id1, timestamp, oracle1_prices)
+        self.nodes[0].generate(120) # let active price update
+        oracle_data = self.nodes[0].getoracledata(self.oracle_id1)
+        assert_equal(len(oracle_data["priceFeeds"]), 2)
+        assert_equal(len(oracle_data["tokenPrices"]), 2)
+
+    def test_setup_tokens(self):
+        print('setting up loan and collateral tokens...')
+        self.nodes[0].setloantoken({
+                    'symbol': self.symboldUSD,
+                    'name': "DUSD stable token",
+                    'fixedIntervalPriceId': "DUSD/USD",
+                    'mintable': True,
+                    'interest': 0})
+
+        self.tokenInterest = Decimal(1)
+        self.nodes[0].setloantoken({
+                    'symbol': self.symbolDOGE,
+                    'name': "DOGE token",
+                    'fixedIntervalPriceId': "DOGE/USD",
+                    'mintable': True,
+                    'interest': Decimal(self.tokenInterest*100)})
+        self.nodes[0].generate(1)
+
+        # Set token ids
+        self.iddUSD = list(self.nodes[0].gettoken(self.symboldUSD).keys())[0]
+        self.idDFI = list(self.nodes[0].gettoken(self.symbolDFI).keys())[0]
+        self.idDOGE = list(self.nodes[0].gettoken(self.symbolDOGE).keys())[0]
+
+        # Mint tokens
+        self.nodes[0].minttokens("1000000@DOGE")
+        self.nodes[0].generate(1)
+        self.nodes[0].minttokens("2000000@" + self.symboldUSD) # necessary for pools
+        self.nodes[0].generate(1)
+
+        # Setup collateral tokens
+        self.nodes[0].setcollateraltoken({
+                    'token': self.idDFI,
+                    'factor': 1,
+                    'fixedIntervalPriceId': "DFI/USD"})
+        self.nodes[0].generate(300)
+
+        assert_equal(len(self.nodes[0].listtokens()), 3)
+        assert_equal(len(self.nodes[0].listloantokens()), 2)
+        assert_equal(len(self.nodes[0].listcollateraltokens()), 1)
+
+
+    def test_setup_poolpairs(self):
+        print("setting up pool pairs...")
+        poolOwner = self.nodes[0].getnewaddress("", "legacy")
+        self.nodes[0].createpoolpair({
+            "tokenA": self.iddUSD,
+            "tokenB": self.idDFI,
+            "commission": Decimal('0.002'),
+            "status": True,
+            "ownerAddress": poolOwner,
+            "pairSymbol": "DUSD-DFI",
+        }, [])
+
+        self.nodes[0].createpoolpair({
+            "tokenA": self.iddUSD,
+            "tokenB": self.idDOGE,
+            "commission": Decimal('0.002'),
+            "status": True,
+            "ownerAddress": poolOwner,
+            "pairSymbol": "DUSD-DOGE",
+        }, [])
+        self.nodes[0].generate(1)
+
+        self.nodes[0].addpoolliquidity({
+            self.account0: ["1000000@" + self.symboldUSD, "1000000@" + self.symbolDFI]
+        }, self.account0, [])
+        self.nodes[0].generate(1)
+
+        self.nodes[0].addpoolliquidity({
+            self.account0: ["1000000@" + self.symboldUSD, "1000@" + self.symbolDOGE]
+        }, self.account0, [])
+        self.nodes[0].generate(1)
+        assert_equal(len(self.nodes[0].listpoolpairs()), 2)
+
+    def test_setup_loan_scheme(self):
+        print("creating loan scheme...")
+        self.loanInterest = Decimal(1)
+        # Create loan schemes and vaults
+        self.nodes[0].createloanscheme(150, Decimal(self.loanInterest*100), 'LOAN150')
+        self.nodes[0].generate(1)
+        assert_equal(len(self.nodes[0].listloanschemes()), 1)
+
+
+    def setup(self):
+        print('Generating initial chain...')
+        self.test_load_account0_with_DFI()
+        self.test_setup_oracles()
+        self.test_setup_tokens()
+        self.test_setup_poolpairs()
+        self.test_setup_loan_scheme()
+
+    def get_new_vault_and_deposit(self, loan_scheme=None, amount=10000):
+        vault_id = self.nodes[0].createvault(self.account0, loan_scheme)
+        self.nodes[0].generate(1)
+        self.nodes[0].deposittovault(vault_id, self.account0, str(amount)+"@DFI") # enough collateral to take loans
+        self.nodes[0].generate(1)
+        return vault_id
+
+    def go_to_FCH(self):
+        blocksUntilFCH = FCH_HEIGHT - self.nodes[0].getblockcount() + 2
+        self.nodes[0].generate(blocksUntilFCH)
+        blockChainInfo = self.nodes[0].getblockchaininfo()
+        assert_equal(blockChainInfo["softforks"]["fortcanninghill"]["active"], True)
+
+    def is_FCH(self):
+        return self.nodes[0].getblockcount() > FCH_HEIGHT
+
+    def test_new_loan_with_interest_lower_than_1satoshi(self, payback=False):
+        vault_id = self.get_new_vault_and_deposit()
+
+        self.nodes[0].takeloan({
+                    'vaultId': vault_id,
+                    'amounts': "0.001314@DOGE"})
+        self.nodes[0].generate(1)
+        vault_data = self.nodes[0].getvault(vault_id)
+        assert_equal(vault_data["interestAmounts"][0], '0.00000001@DOGE')
+
+        self.nodes[0].generate(35)
+        vault_data = self.nodes[0].getvault(vault_id)
+        expected_interest = self.is_FCH() and '0.00000009' or '0.00000036'
+        assert_equal(vault_data["interestAmounts"][0], expected_interest+'@DOGE')
+
+        if not payback:
+            return
+
+        # Payback
+        expected_payback = self.is_FCH() and '0.00131409' or '0.00131436'
+        self.nodes[0].paybackloan({
+                        'vaultId': vault_id,
+                        'from': self.account0,
+                        'amounts': expected_payback+'@DOGE'})
+        self.nodes[0].generate(1)
+        vault_data = self.nodes[0].getvault(vault_id)
+        assert_equal(vault_data["interestAmounts"], [])
+
+
+    def test_new_loan_with_interest_exactly_25satoshi(self, payback=False):
+        vault_id = self.get_new_vault_and_deposit()
+        self.nodes[0].takeloan({
+                    'vaultId': vault_id,
+                    'amounts': "0.1314@DOGE"})
+        self.nodes[0].generate(1)
+        vault_data = self.nodes[0].getvault(vault_id)
+        assert_equal(vault_data["interestAmounts"][0], '0.00000025@DOGE')
+
+        self.nodes[0].generate(35)
+        vault_data = self.nodes[0].getvault(vault_id)
+        assert_equal(vault_data["interestAmounts"][0], '0.00000900@DOGE')
+
+        if not payback:
+            return
+
+        # Payback
+        self.nodes[0].paybackloan({
+                        'vaultId': vault_id,
+                        'from': self.account0,
+                        'amounts': '0.13140900@DOGE'})
+        self.nodes[0].generate(1)
+        vault_data = self.nodes[0].getvault(vault_id)
+        assert_equal(vault_data["interestAmounts"], [])
+
+    def test_new_loan_with_interest_over_1satoshi(self, payback=False):
+        vault_id = self.get_new_vault_and_deposit()
+        self.nodes[0].takeloan({
+                    'vaultId': vault_id,
+                    'amounts': "100@DOGE"})
+        self.nodes[0].generate(1)
+        vault_data = self.nodes[0].getvault(vault_id)
+        assert_equal(vault_data["interestAmounts"][0], '0.00019026@DOGE')
+
+        self.nodes[0].generate(35)
+        vault_data = self.nodes[0].getvault(vault_id)
+        expected_interest = self.is_FCH() and '0.00684932' or '0.00684936'
+        assert_equal(vault_data["interestAmounts"][0], expected_interest+'@DOGE')
+
+        if not payback:
+            return
+        # Payback
+        expected_payback = self.is_FCH() and '100.00684932' or '100.00684936'
+        self.nodes[0].paybackloan({
+                        'vaultId': vault_id,
+                        'from': self.account0,
+                        'amounts': expected_payback+'@DOGE'})
+        self.nodes[0].generate(1)
+        vault_data = self.nodes[0].getvault(vault_id)
+        assert_equal(vault_data["interestAmounts"], [])
+
+    def test_low_loan(self, payback=False):
+        vault_id = self.get_new_vault_and_deposit()
+        self.nodes[0].takeloan({
+                    'vaultId': vault_id,
+                    'amounts': "0.00000001@DOGE"})
+        self.nodes[0].generate(1)
+        vault_data = self.nodes[0].getvault(vault_id)
+        assert_equal(vault_data["interestAmounts"][0], '0.00000001@DOGE')
+
+        self.nodes[0].generate(35)
+        vault_data = self.nodes[0].getvault(vault_id)
+        expected_interest = self.is_FCH() and '0.00000001' or '0.00000036'
+        assert_equal(vault_data["interestAmounts"][0], expected_interest+'@DOGE')
+
+        if not payback:
+            return
+        # Payback
+        expected_payback = self.is_FCH() and '0.00000002' or '0.00000037'
+        self.nodes[0].paybackloan({
+                        'vaultId': vault_id,
+                        'from': self.account0,
+                        'amounts': expected_payback+'@DOGE'})
+        self.nodes[0].generate(1)
+        vault_data = self.nodes[0].getvault(vault_id)
+        assert_equal(vault_data["interestAmounts"], [])
+
+    def test_high_loan(self, payback=False):
+        vault_id = self.get_new_vault_and_deposit()
+        self.nodes[0].takeloan({
+                    'vaultId': vault_id,
+                    'amounts': "2345.225@DOGE"})
+        self.nodes[0].generate(1)
+        vault_data = self.nodes[0].getvault(vault_id)
+        assert_equal(vault_data["interestAmounts"][0], '0.00446200@DOGE')
+
+        self.nodes[0].generate(35)
+        vault_data = self.nodes[0].getvault(vault_id)
+        expected_interest = self.is_FCH() and '0.16063185' or '0.16063200'
+        assert_equal(vault_data["interestAmounts"][0], expected_interest+'@DOGE')
+
+        if not payback:
+            return
+        # Payback
+        expected_payback = self.is_FCH() and '2345.38563185' or '2345.38563200'
+        self.nodes[0].paybackloan({
+                        'vaultId': vault_id,
+                        'from': self.account0,
+                        'amounts': expected_payback+'@DOGE'})
+        self.nodes[0].generate(1)
+        vault_data = self.nodes[0].getvault(vault_id)
+        assert_equal(vault_data["interestAmounts"], [])
+
+
+    def run_test(self):
+        self.setup()
+
+        # PRE FCH
+        self.test_new_loan_with_interest_lower_than_1satoshi(payback=True)
+        self.test_new_loan_with_interest_exactly_25satoshi(payback=True)
+        self.test_new_loan_with_interest_over_1satoshi(payback=True)
+        self.test_new_loan_with_interest_lower_than_1satoshi()
+        self.test_new_loan_with_interest_exactly_25satoshi()
+        self.test_new_loan_with_interest_over_1satoshi()
+        # limit amounts pre FCH
+        self.test_low_loan(payback=True)
+        self.test_high_loan(payback=True)
+        self.test_low_loan()
+        self.test_high_loan()
+
+        self.go_to_FCH()
+
+        self.test_new_loan_with_interest_lower_than_1satoshi(payback=True)
+        self.test_new_loan_with_interest_exactly_25satoshi(payback=True)
+        self.test_new_loan_with_interest_over_1satoshi(payback=True)
+        self.test_new_loan_with_interest_lower_than_1satoshi()
+        self.test_new_loan_with_interest_exactly_25satoshi()
+        self.test_new_loan_with_interest_over_1satoshi()
+        # limit amounts post FCH
+        self.test_low_loan(payback=True)
+        self.test_high_loan(payback=True)
+        self.test_low_loan()
+        self.test_high_loan()
+
+if __name__ == '__main__':
+    LowInterestTest().main()
diff --git a/test/functional/feature_loan_vault.py b/test/functional/feature_loan_vault.py
index 90933f2921..2411052113 100755
--- a/test/functional/feature_loan_vault.py
+++ b/test/functional/feature_loan_vault.py
@@ -18,8 +18,8 @@ def set_test_params(self):
         self.num_nodes = 2
         self.setup_clean_chain = True
         self.extra_args = [
-                ['-txnotokens=0', '-amkheight=1', '-bayfrontheight=1', '-bayfrontgardensheight=1', '-eunosheight=1', '-txindex=1', '-fortcanningheight=1', '-fortcanninghillheight=1', '-jellyfish_regtest=1'],
-                ['-txnotokens=0', '-amkheight=1', '-bayfrontheight=1', '-bayfrontgardensheight=1', '-eunosheight=1', '-txindex=1', '-fortcanningheight=1', '-fortcanninghillheight=1', '-jellyfish_regtest=1']
+                ['-txnotokens=0', '-amkheight=1', '-bayfrontheight=1', '-bayfrontgardensheight=1', '-eunosheight=1', '-txindex=1', '-fortcanningheight=1', '-fortcanninghillheight=300', '-jellyfish_regtest=1'],
+                ['-txnotokens=0', '-amkheight=1', '-bayfrontheight=1', '-bayfrontgardensheight=1', '-eunosheight=1', '-txindex=1', '-fortcanningheight=1', '-fortcanninghillheight=300', '-jellyfish_regtest=1']
             ]
 
     def run_test(self):
diff --git a/test/functional/test_runner.py b/test/functional/test_runner.py
index fa02e455f4..160dbf21dc 100755
--- a/test/functional/test_runner.py
+++ b/test/functional/test_runner.py
@@ -262,6 +262,7 @@
     'feature_loan_priceupdate.py',
     'feature_loan_vaultstate.py',
     'feature_loan.py',
+    'feature_loan_low_interest.py',
     'feature_loan_estimatecollateral.py',
     'p2p_node_network_limited.py',
     'p2p_permissions.py',
diff --git a/test/lint/lint-python-dead-code-whitelist b/test/lint/lint-python-dead-code-whitelist
index ddfdbf03ea..f1751bba76 100644
--- a/test/lint/lint-python-dead-code-whitelist
+++ b/test/lint/lint-python-dead-code-whitelist
@@ -46,3 +46,4 @@ SpendTooMuch  # unused class (test/functional/data/invalid_txs.py)
 TooManySigops  # unused class (test/functional/data/invalid_txs.py)
 verify_ecdsa  # unused function (test/functional/test_framework/key.py)
 AnchorRewardsTest  # unused class (test/functional/feature_anchor_rewards.py)
+_.prec  # unused attribute (test/functional/feature_loan_low_interest.py)

From c33500fd7735c9811d61738a1d9f3937ef44292f Mon Sep 17 00:00:00 2001
From: D <55594560+hidiego@users.noreply.github.com>
Date: Mon, 24 Jan 2022 18:55:17 +0100
Subject: [PATCH 4/5] Use head commit instead of base branch merge for PR tests
 (#1051)

* Update Test workflow to checkout PR HEAD

Co-authored-by: Prasanna Loganathar <pvl@prasannavl.com>
---
 .github/workflows/tests.yaml | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/tests.yaml b/.github/workflows/tests.yaml
index 1fe3fd1bb6..3fdc63324b 100644
--- a/.github/workflows/tests.yaml
+++ b/.github/workflows/tests.yaml
@@ -38,8 +38,15 @@ jobs:
       TRAVIS_BUILD_DIR: ${{ github.workspace }}
       TRAVIS_COMMIT: ${{ github.sha }}
     steps:
-    - name: Checkout
-      uses: actions/checkout@v1
+    - name: Checkout base branch and/or merge
+      if: github.event_name != 'pull_request'
+      uses: actions/checkout@v2
+
+    - name: Checkout pull request head commit
+      if: github.event_name == 'pull_request'
+      uses: actions/checkout@v2
+      with:
+        ref: ${{ github.event.pull_request.head.sha }}
 
     # This script has been modified to pipe variables to GITHUB_ENV, which allows them to be
     # used by subsequent steps.

From 4fefd57ffa107308e003421abca439f7d6291fdb Mon Sep 17 00:00:00 2001
From: Peter John Bushnell <bushsolo@gmail.com>
Date: Mon, 24 Jan 2022 19:11:05 +0000
Subject: [PATCH 5/5] Rename vars. Update test to avoid errors. (#1050)

* Rename vars. Update test to avoid errors.

* Use single node for test

* Erase SmartContract history on rollback

Co-authored-by: Prasanna Loganathar <pvl@prasannavl.com>
---
 src/masternodes/mn_checks.cpp              |  19 ++--
 test/functional/feature_smart_contracts.py | 118 ++++++++-------------
 2 files changed, 60 insertions(+), 77 deletions(-)

diff --git a/src/masternodes/mn_checks.cpp b/src/masternodes/mn_checks.cpp
index 732d87c6bb..8d5c2b09db 100644
--- a/src/masternodes/mn_checks.cpp
+++ b/src/masternodes/mn_checks.cpp
@@ -1431,19 +1431,19 @@ class CCustomTxApplyVisitor : public CCustomTxVisitor
                 return std::move(resVal);
             }
 
-            CDataStructureV0 premiumKey{AttributeTypes::Param, ParamIDs::DFIP2201, DFIP2201Keys::Premium};
-            CAmount premium{2500000};
+            CDataStructureV0 feePctKey{AttributeTypes::Param, ParamIDs::DFIP2201, DFIP2201Keys::Premium};
+            CAmount feePct{2500000};
             try {
-                const auto& value = attrs.at(premiumKey);
+                const auto& value = attrs.at(feePctKey);
                 auto valueV0 = boost::get<const CValueV0>(&value);
                 if (valueV0) {
-                    if (auto storedPremium = boost::get<const CAmount>(valueV0)) {
-                        premium = *storedPremium;
+                    if (auto storedFeePct = boost::get<const CAmount>(valueV0)) {
+                        feePct = *storedFeePct;
                     }
                 }
             } catch (const std::out_of_range&) {}
 
-            const auto& btcPrice = MultiplyAmounts(resVal.val.get(), premium + COIN);
+            const auto& btcPrice = MultiplyAmounts(resVal.val.get(), feePct + COIN);
 
             resVal = mnview.GetValidatedIntervalPrice(dfiUsd, useNextPrice, requireLivePrice);
             if (!resVal) {
@@ -3056,6 +3056,13 @@ class CCustomTxRevertVisitor : public CCustomTxVisitor
         return EraseHistory(obj.from);
     }
 
+    Res operator()(const CSmartContractMessage& obj) const {
+        for (const auto& account : obj.accounts) {
+            EraseHistory(account.first);
+        }
+        return Res::Ok();
+    }
+
     Res operator()(const CAnyAccountsToAccountsMessage& obj) const {
         for (const auto& account : obj.to) {
             EraseHistory(account.first);
diff --git a/test/functional/feature_smart_contracts.py b/test/functional/feature_smart_contracts.py
index ed05397be3..2eebf857b3 100644
--- a/test/functional/feature_smart_contracts.py
+++ b/test/functional/feature_smart_contracts.py
@@ -13,34 +13,29 @@
 
 class SmartContractTest(DefiTestFramework):
     def set_test_params(self):
-        self.num_nodes = 2
+        self.num_nodes = 1
         self.setup_clean_chain = True
-        self.extra_args = [['-txnotokens=0', '-amkheight=1', '-bayfrontheight=1', '-eunosheight=1', '-fortcanningheight=1', '-fortcanninghillheight=1010', '-subsidytest=1', '-txindex=1', '-jellyfish_regtest=1'],
-                           ['-txnotokens=0', '-amkheight=1', '-bayfrontheight=1', '-eunosheight=1', '-fortcanningheight=1', '-fortcanninghillheight=1010', '-subsidytest=1', '-txindex=1', '-jellyfish_regtest=1']]
+        self.extra_args = [['-txnotokens=0', '-amkheight=1', '-bayfrontheight=1', '-eunosheight=1', '-fortcanningheight=1', '-fortcanninghillheight=1010', '-subsidytest=1', '-txindex=1', '-jellyfish_regtest=1']]
 
     def rollback(self, count):
         block = self.nodes[0].getblockhash(count)
         self.nodes[0].invalidateblock(block)
-        self.nodes[1].invalidateblock(block)
         self.nodes[0].clearmempool()
-        self.nodes[1].clearmempool()
-        self.sync_blocks()
 
     def run_test(self):
         self.nodes[0].generate(1000)
-        self.sync_blocks()
 
-        address = self.nodes[1].getnewaddress("", "legacy")
-        invalid_address = self.nodes[0].getnewaddress("", "legacy")
+        address = self.nodes[0].getnewaddress("", "legacy")
+        invalid_address = 'mrV4kYRhyrfiCcpfXDSZuhe56kCQu84gqh'
         dfi_amount = 1000
         btc_amount = 1
         dfip = 'dbtcdfiswap'
 
         # Check invalid calls
-        assert_raises_rpc_error(-5, 'Incorrect authorization for {}'.format(invalid_address), self.nodes[1].executesmartcontract, dfip, str(btc_amount) + '@2', invalid_address)
+        assert_raises_rpc_error(-5, 'Incorrect authorization for {}'.format(invalid_address), self.nodes[0].executesmartcontract, dfip, str(btc_amount) + '@2', invalid_address)
         assert_raises_rpc_error(-4, 'Insufficient funds', self.nodes[0].executesmartcontract, dfip, str(dfi_amount) + '@0')
-        assert_raises_rpc_error(-8, 'Specified smart contract not found', self.nodes[1].executesmartcontract, 'DFIP9999', str(dfi_amount) + '@0')
-        assert_raises_rpc_error(-8, 'BTC source address must be provided for DFIP2201', self.nodes[1].executesmartcontract, dfip, str(btc_amount) + '@2')
+        assert_raises_rpc_error(-8, 'Specified smart contract not found', self.nodes[0].executesmartcontract, 'DFIP9999', str(dfi_amount) + '@0')
+        assert_raises_rpc_error(-8, 'BTC source address must be provided for DFIP2201', self.nodes[0].executesmartcontract, dfip, str(btc_amount) + '@2')
 
         # Create tokens
         self.nodes[0].createtoken({
@@ -59,48 +54,43 @@ def run_test(self):
         self.nodes[0].generate(1)
 
         # Create and fund address with BTC
-        address = self.nodes[1].getnewaddress("", "legacy")
+        address = self.nodes[0].getnewaddress("", "legacy")
         self.nodes[0].minttokens("100000@BTC")
         self.nodes[0].generate(1)
         self.nodes[0].accounttoaccount(self.nodes[0].get_genesis_keys().ownerAuthAddress, {address: "20000@BTC"})
         self.nodes[0].generate(1)
-        for _ in range(20):
-            self.nodes[0].sendtoaddress(address, 0.1)
-        self.nodes[0].generate(1)
-        self.sync_blocks()
 
         # Check invalid calls
-        assert_raises_rpc_error(-32600, 'called before FortCanningHill height', self.nodes[1].executesmartcontract, dfip, str(btc_amount) + '@2', address)
+        assert_raises_rpc_error(-32600, 'called before FortCanningHill height', self.nodes[0].executesmartcontract, dfip, str(btc_amount) + '@2', address)
 
         # Move to FortCanningHill
         self.nodes[0].generate(1010 - self.nodes[0].getblockcount())
-        self.sync_blocks()
 
         # Check invalid call
-        assert_raises_rpc_error(-32600, 'DFIP2201 smart contract is not enabled', self.nodes[1].executesmartcontract, dfip, str(btc_amount) + '@2', address)
+        assert_raises_rpc_error(-32600, 'DFIP2201 smart contract is not enabled', self.nodes[0].executesmartcontract, dfip, str(btc_amount) + '@2', address)
 
         self.nodes[0].setgov({"ATTRIBUTES":{'v0/params/dfip2201/active':'false'}})
         self.nodes[0].generate(1)
 
         # Check invalid call
-        assert_raises_rpc_error(-32600, 'DFIP2201 smart contract is not enabled', self.nodes[1].executesmartcontract, dfip, str(btc_amount) + '@2', address)
+        assert_raises_rpc_error(-32600, 'DFIP2201 smart contract is not enabled', self.nodes[0].executesmartcontract, dfip, str(btc_amount) + '@2', address)
 
         self.nodes[0].setgov({"ATTRIBUTES":{'v0/params/dfip2201/active':'true'}})
         self.nodes[0].generate(1)
 
         # Check invalid calls
-        assert_raises_rpc_error(-32600, 'is less than', self.nodes[1].executesmartcontract, dfip, '20000.00000001@2', address)
-        assert_raises_rpc_error(-3, 'Amount out of range', self.nodes[1].executesmartcontract, dfip, '0@2', address)
-        assert_raises_rpc_error(-32600, 'Specified token not found', self.nodes[1].executesmartcontract, dfip, str(btc_amount) + '@9999', address)
-        assert_raises_rpc_error(-32600, 'Only Bitcoin can be swapped in DFIP2201', self.nodes[1].executesmartcontract, dfip, str(btc_amount) + '@1', address)
-        assert_raises_rpc_error(-32600, 'fixedIntervalPrice with id <BTC/USD> not found', self.nodes[1].executesmartcontract, dfip, str(btc_amount) + '@2', address)
+        assert_raises_rpc_error(-32600, 'is less than', self.nodes[0].executesmartcontract, dfip, '20000.00000001@2', address)
+        assert_raises_rpc_error(-3, 'Amount out of range', self.nodes[0].executesmartcontract, dfip, '0@2', address)
+        assert_raises_rpc_error(-32600, 'Specified token not found', self.nodes[0].executesmartcontract, dfip, str(btc_amount) + '@9999', address)
+        assert_raises_rpc_error(-32600, 'Only Bitcoin can be swapped in DFIP2201', self.nodes[0].executesmartcontract, dfip, str(btc_amount) + '@1', address)
+        assert_raises_rpc_error(-32600, 'fixedIntervalPrice with id <BTC/USD> not found', self.nodes[0].executesmartcontract, dfip, str(btc_amount) + '@2', address)
 
         # Test min swap
         self.nodes[0].setgov({"ATTRIBUTES":{'v0/params/dfip2201/minswap':'0.00001'}})
         self.nodes[0].generate(1)
 
         # Check invalid calls
-        assert_raises_rpc_error(-32600, 'Below minimum swapable amount, must be at least 0.00001000 BTC', self.nodes[1].executesmartcontract, dfip, '0.00000999@2', address)
+        assert_raises_rpc_error(-32600, 'Below minimum swapable amount, must be at least 0.00001000 BTC', self.nodes[0].executesmartcontract, dfip, '0.00000999@2', address)
 
         # Set up oracles
         oracle_address = self.nodes[0].getnewaddress("", "legacy")
@@ -125,14 +115,13 @@ def run_test(self):
                                     'fixedIntervalPriceId': "BTC/USD"})
 
         self.nodes[0].generate(7)
-        self.sync_blocks()
 
         # Import community balance
-        self.nodes[1].importprivkey('cMv1JaaZ9Mbb3M3oNmcFvko8p7EcHJ8XD7RCQjzNaMs7BWRVZTyR')
-        balance = self.nodes[1].getbalance()
+        self.nodes[0].importprivkey('cMv1JaaZ9Mbb3M3oNmcFvko8p7EcHJ8XD7RCQjzNaMs7BWRVZTyR')
+        balance = self.nodes[0].getbalance()
 
         # Try and fund more than is in community balance
-        assert_raises_rpc_error(-4, 'Insufficient funds', self.nodes[1].executesmartcontract, dfip, '18336.22505381@0', address)
+        assert_raises_rpc_error(-4, 'Insufficient funds', self.nodes[0].executesmartcontract, dfip, '18336.22505381@0', address)
 
         # Check smart contract details and balance
         result = self.nodes[0].listsmartcontracts()
@@ -142,9 +131,8 @@ def run_test(self):
         assert('0' not in result[0])
 
         # Fund smart contract
-        tx = self.nodes[1].executesmartcontract(dfip, '18336.225@0')
-        self.nodes[1].generate(1)
-        self.sync_blocks()
+        tx = self.nodes[0].executesmartcontract(dfip, '18336.225@0')
+        self.nodes[0].generate(1)
 
         # Check smart contract details and balance
         result = self.nodes[0].listsmartcontracts()
@@ -152,21 +140,21 @@ def run_test(self):
 
         # Check balance has changed as expected
         block = self.nodes[0].getblock(self.nodes[0].getblockhash(self.nodes[0].getblockcount() - 100))
-        community_reward = self.nodes[0].getrawtransaction(block['tx'][0], 1)['vout'][1]['value']
-        fee = self.nodes[1].gettransaction(tx)['fee']
-        assert_equal(balance + community_reward - Decimal('18336.225') + fee, self.nodes[1].getbalance())
+        rewards = self.nodes[0].getrawtransaction(block['tx'][0], 1)['vout']
+        staker_reward = rewards[0]['value']
+        community_reward = rewards[1]['value']
+        fee = self.nodes[0].gettransaction(tx)['fee']
+        assert_equal(balance + staker_reward + community_reward - Decimal('18336.225') + fee, self.nodes[0].getbalance())
 
         # Test swap for more than in community fund by 1 Sat
         block = self.nodes[0].getblockcount() + 1
         self.nodes[0].setgov({"ATTRIBUTES":{'v0/params/dfip2201/premium':'0.00000000'}})
         self.nodes[0].generate(1)
-        self.sync_blocks()
-        assert_raises_rpc_error(-32600, 'amount 18336.22500000 is less than 18336.22500001', self.nodes[1].executesmartcontract, dfip, '18336.22500001@2', address)
+        assert_raises_rpc_error(-32600, 'amount 18336.22500000 is less than 18336.22500001', self.nodes[0].executesmartcontract, dfip, '18336.22500001@2', address)
 
         # Test again for full amount in community balance
-        self.nodes[1].executesmartcontract(dfip, '18336.22500000@2', address)
-        self.nodes[1].generate(1)
-        self.sync_blocks()
+        self.nodes[0].executesmartcontract(dfip, '18336.22500000@2', address)
+        self.nodes[0].generate(1)
         assert_equal(18336.22500000, float(self.nodes[0].getaccount(address)[0].split('@')[0]))
         assert('0' not in self.nodes[0].listsmartcontracts())
 
@@ -179,80 +167,68 @@ def run_test(self):
 
         # Test default 2.5% premium
         block = self.nodes[0].getblockcount() + 1
-        self.nodes[1].executesmartcontract(dfip, '0.09999999@2', address)
-        self.nodes[1].generate(1)
-        self.sync_blocks()
+        self.nodes[0].executesmartcontract(dfip, '0.09999999@2', address)
+        self.nodes[0].generate(1)
         assert_equal(2049.999795, float(self.nodes[0].getaccount(address)[0].split('@')[0]))
 
         # Test 5% premium
         self.rollback(block)
         self.nodes[0].setgov({"ATTRIBUTES":{'v0/params/dfip2201/premium':'0.05'}})
         self.nodes[0].generate(1)
-        self.sync_blocks()
-        self.nodes[1].executesmartcontract(dfip, '0.09999999@2', address)
-        self.nodes[1].generate(1)
-        self.sync_blocks()
+        self.nodes[0].executesmartcontract(dfip, '0.09999999@2', address)
+        self.nodes[0].generate(1)
         assert_equal(2099.99979, float(self.nodes[0].getaccount(address)[0].split('@')[0]))
 
         # Test 0.1% premium
         self.rollback(block)
         self.nodes[0].setgov({"ATTRIBUTES":{'v0/params/dfip2201/premium':'0.001'}})
         self.nodes[0].generate(1)
-        self.sync_blocks()
-        self.nodes[1].executesmartcontract(dfip, '0.09999999@2', address)
-        self.nodes[1].generate(1)
-        self.sync_blocks()
+        self.nodes[0].executesmartcontract(dfip, '0.09999999@2', address)
+        self.nodes[0].generate(1)
         assert_equal(2001.9997998, float(self.nodes[0].getaccount(address)[0].split('@')[0]))
 
         # Test 0.000001% premium
         self.rollback(block)
         self.nodes[0].setgov({"ATTRIBUTES":{'v0/params/dfip2201/premium':'0.00000001'}})
         self.nodes[0].generate(1)
-        self.sync_blocks()
-        self.nodes[1].executesmartcontract(dfip, '0.1@2', address)
-        self.nodes[1].generate(1)
-        self.sync_blocks()
+        self.nodes[0].executesmartcontract(dfip, '0.1@2', address)
+        self.nodes[0].generate(1)
         assert_equal(2000.00002, float(self.nodes[0].getaccount(address)[0].split('@')[0]))
 
         # Test 0% premium
         self.rollback(block)
         self.nodes[0].setgov({"ATTRIBUTES":{'v0/params/dfip2201/premium':'0.00000000'}})
         self.nodes[0].generate(1)
-        self.sync_blocks()
-        self.nodes[1].executesmartcontract(dfip, '0.1@2', address)
-        self.nodes[1].generate(1)
-        self.sync_blocks()
+        self.nodes[0].executesmartcontract(dfip, '0.1@2', address)
+        self.nodes[0].generate(1)
         assert_equal(2000, float(self.nodes[0].getaccount(address)[0].split('@')[0]))
 
         # Swap min amount
         self.rollback(block)
-        self.nodes[1].executesmartcontract(dfip, '0.00001@2', address)
-        self.nodes[1].generate(1)
-        self.sync_blocks()
+        self.nodes[0].executesmartcontract(dfip, '0.00001@2', address)
+        self.nodes[0].generate(1)
         assert_equal(0.205, float(self.nodes[0].getaccount(address)[0].split('@')[0]))
 
         # Test smallest min amount
         self.rollback(block)
         self.nodes[0].setgov({"ATTRIBUTES":{'v0/params/dfip2201/minswap':'0.00000001'}})
         self.nodes[0].generate(1)
-        self.nodes[1].executesmartcontract(dfip, '0.00000001@2', address)
-        self.nodes[1].generate(1)
-        self.sync_blocks()
+        self.nodes[0].executesmartcontract(dfip, '0.00000001@2', address)
+        self.nodes[0].generate(1)
         assert_equal(0.000205, float(self.nodes[0].getaccount(address)[0].split('@')[0]))
 
         # Test no smallest min amount
         self.rollback(block)
         self.nodes[0].setgov({"ATTRIBUTES":{'v0/params/dfip2201/minswap':'0.00000001'}})
         self.nodes[0].generate(1)
-        self.nodes[1].executesmartcontract(dfip, '0.00000001@2', address)
-        self.nodes[1].generate(1)
-        self.sync_blocks()
+        self.nodes[0].executesmartcontract(dfip, '0.00000001@2', address)
+        self.nodes[0].generate(1)
         assert_equal(0.000205, float(self.nodes[0].getaccount(address)[0].split('@')[0]))
 
         # Test disabling DFIP201
         self.nodes[0].setgov({"ATTRIBUTES":{'v0/params/dfip2201/active':'false'}})
         self.nodes[0].generate(1)
-        assert_raises_rpc_error(-32600, 'DFIP2201 smart contract is not enabled', self.nodes[1].executesmartcontract, dfip, '1@2', address)
+        assert_raises_rpc_error(-32600, 'DFIP2201 smart contract is not enabled', self.nodes[0].executesmartcontract, dfip, '1@2', address)
 
 if __name__ == '__main__':
     SmartContractTest().main()