diff --git a/src/etl/MPTHelpers.cpp b/src/etl/MPTHelpers.cpp
index 00eadc5d..23767cbe 100644
--- a/src/etl/MPTHelpers.cpp
+++ b/src/etl/MPTHelpers.cpp
@@ -18,6 +18,7 @@
 //==============================================================================
 
 #include "data/DBHelpers.hpp"
+#include "util/Assert.hpp"
 
 #include <ripple/protocol/STBase.h>
 #include <ripple/protocol/STTx.h>
@@ -71,6 +72,9 @@ getMPTHolderFromTx(ripple::TxMeta const& txMeta, ripple::STTx const& sttx)
 std::optional<MPTHolderData>
 getMPTHolderFromObj(std::string const& key, std::string const& blob)
 {
+    // https://github.com/XRPLF/XRPL-Standards/tree/master/XLS-0033-multi-purpose-tokens#2121-mptoken-ledger-identifier
+    ASSERT(key.size() == ripple::uint256::size(), "The size of the key is expected to fit uint256 exactly");
+
     ripple::STLedgerEntry const sle =
         ripple::STLedgerEntry(ripple::SerialIter{blob.data(), blob.size()}, ripple::uint256::fromVoid(key.data()));
 
diff --git a/tests/common/util/BinaryTestObject.cpp b/tests/common/util/BinaryTestObject.cpp
index d03a2ef6..25ee516e 100644
--- a/tests/common/util/BinaryTestObject.cpp
+++ b/tests/common/util/BinaryTestObject.cpp
@@ -37,6 +37,7 @@
 #include <xrpl/protocol/Serializer.h>
 #include <xrpl/protocol/TxFormats.h>
 #include <xrpl/protocol/TxMeta.h>
+#include <xrpl/protocol/digest.h>
 
 #include <optional>
 #include <string>
@@ -152,7 +153,7 @@ createObjectWithTwoNFTs()
 
     // key is a token made up from owner's account ID followed by unused (in Clio) value described here:
     // https://github.com/XRPLF/XRPL-Standards/tree/master/XLS-0020-non-fungible-tokens#tokenpage-id-format
-    auto constexpr kEXTRA_BYTES = "000000000000";
+    constexpr auto kEXTRA_BYTES = "000000000000";
     auto const key = std::string(std::begin(account), std::end(account)) + kEXTRA_BYTES;
 
     return {
@@ -173,11 +174,17 @@ createObjectWithMPT()
     constexpr auto kACCOUNT = "rM2AGCCCRb373FRuD8wHyUwUsh2dV4BW5Q";
 
     auto const account = getAccountIdWithString(kACCOUNT);
-    auto const mptokenObject = createMpTokenObject(kACCOUNT, ripple::makeMptID(2, getAccountIdWithString(kACCOUNT)));
+    auto const mptID = ripple::makeMptID(2, getAccountIdWithString(kACCOUNT));
+    auto const mptokenObject = createMpTokenObject(kACCOUNT, mptID);
+
+    // key is a token made up from several fields described here:
+    // https://github.com/XRPLF/XRPL-Standards/tree/master/XLS-0033-multi-purpose-tokens#2121-mptoken-ledger-identifier
+    constexpr auto kSPACE_KEY = 0x007F;
+    auto const keySha512Half = ripple::sha512Half(kSPACE_KEY, mptID, account);
 
     return {
         .key = {},
-        .keyRaw = std::string(reinterpret_cast<char const*>(account.data()), ripple::AccountID::size()),
+        .keyRaw = std::string(std::begin(keySha512Half), std::end(keySha512Half)),
         .data = {},
         .dataRaw = std::string(
             static_cast<char const*>(mptokenObject.getSerializer().getDataPtr()),
diff --git a/tests/integration/migration/cassandra/CassandraMigrationManagerTests.cpp b/tests/integration/migration/cassandra/CassandraMigrationManagerTests.cpp
index d8528aa7..393b4249 100644
--- a/tests/integration/migration/cassandra/CassandraMigrationManagerTests.cpp
+++ b/tests/integration/migration/cassandra/CassandraMigrationManagerTests.cpp
@@ -223,7 +223,7 @@ class MigrationCassandraManagerTxTableTest : public MigrationCassandraSimpleTest
 
 TEST_F(MigrationCassandraManagerTxTableTest, MigrateExampleTransactionsMigrator)
 {
-    auto constexpr kTRANSACTIONS_MIGRATOR_NAME = "ExampleTransactionsMigrator";
+    constexpr auto kTRANSACTIONS_MIGRATOR_NAME = "ExampleTransactionsMigrator";
     EXPECT_EQ(testMigrationManager_->getMigratorStatusByName(kTRANSACTIONS_MIGRATOR_NAME), MigratorStatus::NotMigrated);
 
     ExampleTransactionsMigrator::count = 0;
@@ -274,7 +274,7 @@ class MigrationCassandraManagerObjectsTableTest : public MigrationCassandraSimpl
 
 TEST_F(MigrationCassandraManagerObjectsTableTest, MigrateExampleObjectsMigrator)
 {
-    auto constexpr kOBJECTS_MIGRATOR_NAME = "ExampleObjectsMigrator";
+    constexpr auto kOBJECTS_MIGRATOR_NAME = "ExampleObjectsMigrator";
     EXPECT_EQ(testMigrationManager_->getMigratorStatusByName(kOBJECTS_MIGRATOR_NAME), MigratorStatus::NotMigrated);
 
     testMigrationManager_->runMigration(kOBJECTS_MIGRATOR_NAME);
@@ -302,7 +302,7 @@ class MigrationCassandraManagerLedgerTableTest : public MigrationCassandraSimple
 
 TEST_F(MigrationCassandraManagerLedgerTableTest, MigrateExampleLedgerMigrator)
 {
-    auto constexpr kHEADER_MIGRATOR_NAME = "ExampleLedgerMigrator";
+    constexpr auto kHEADER_MIGRATOR_NAME = "ExampleLedgerMigrator";
     EXPECT_EQ(testMigrationManager_->getMigratorStatusByName(kHEADER_MIGRATOR_NAME), MigratorStatus::NotMigrated);
 
     testMigrationManager_->runMigration(kHEADER_MIGRATOR_NAME);
@@ -334,7 +334,7 @@ class MigrationCassandraManagerDropTableTest : public MigrationCassandraSimpleTe
 
 TEST_F(MigrationCassandraManagerDropTableTest, MigrateDropTableMigrator)
 {
-    auto constexpr kDROP_TABLE_MIGRATOR_NAME = "ExampleDropTableMigrator";
+    constexpr auto kDROP_TABLE_MIGRATOR_NAME = "ExampleDropTableMigrator";
     EXPECT_EQ(testMigrationManager_->getMigratorStatusByName(kDROP_TABLE_MIGRATOR_NAME), MigratorStatus::NotMigrated);
 
     auto const beforeDropSize =
diff --git a/tests/unit/etl/NFTHelpersTests.cpp b/tests/unit/etl/NFTHelpersTests.cpp
index a5bed974..4bb44a7b 100644
--- a/tests/unit/etl/NFTHelpersTests.cpp
+++ b/tests/unit/etl/NFTHelpersTests.cpp
@@ -478,7 +478,7 @@ TEST_F(NFTHelpersTest, NFTDataFromLedgerObject)
 
     // key is a token made up from owner's account ID followed by unused (in Clio) value described here:
     // https://github.com/XRPLF/XRPL-Standards/tree/master/XLS-0020-non-fungible-tokens#tokenpage-id-format
-    auto constexpr kEXTRA_BYTES = "000000000000";
+    constexpr auto kEXTRA_BYTES = "000000000000";
     auto const key = std::string(std::begin(account), std::end(account)) + kEXTRA_BYTES;
 
     uint32_t constexpr kSEQ{5};
diff --git a/tests/unit/rpc/RPCHelpersTests.cpp b/tests/unit/rpc/RPCHelpersTests.cpp
index 7123fd48..f607fa89 100644
--- a/tests/unit/rpc/RPCHelpersTests.cpp
+++ b/tests/unit/rpc/RPCHelpersTests.cpp
@@ -419,7 +419,7 @@ TEST_F(RPCHelpersTest, DeliverMaxAliasV1)
 
 TEST_F(RPCHelpersTest, DeliverMaxAliasV2)
 {
-    auto constexpr kJSON = R"JSON({
+    constexpr auto kJSON = R"JSON({
          "TransactionType": "Payment",
          "Amount": {
              "test": "test"
@@ -522,7 +522,7 @@ TEST_F(RPCHelpersTest, TransactionAndMetadataBinaryJsonV2)
 
 TEST_F(RPCHelpersTest, ParseIssue)
 {
-    auto constexpr kJSON = R"JSON({
+    constexpr auto kJSON = R"JSON({
         "issuer": "rLEsXccBGNR3UPuPu2hUXPjziKC3qKSBun",
         "currency": "JPY"
     })JSON";
@@ -536,7 +536,7 @@ TEST_F(RPCHelpersTest, ParseIssue)
 
     EXPECT_THROW(parseIssue(boost::json::parse(R"JSON({"currency": "XRP2"})JSON").as_object()), std::runtime_error);
 
-    auto constexpr kJSON2 = R"JSON({
+    constexpr auto kJSON2 = R"JSON({
         "issuer": "abcd",
         "currency": "JPY"
     })JSON";