diff --git a/src/chainparams.cpp b/src/chainparams.cpp
index 85e5bb314..1ce12de65 100644
--- a/src/chainparams.cpp
+++ b/src/chainparams.cpp
@@ -20,7 +20,7 @@
 static CBlock CreateGenesisBlock(const char* pszTimestamp, const CScript& genesisOutputScript, uint32_t nTime, const uint256& nNonce, const std::vector<unsigned char>& nSolution, uint32_t nBits, int32_t nVersion, const CAmount& genesisReward)
 {
     // To create a genesis block for a new chain which is Overwintered:
-    //   txNew.nVersion = 3
+    //   txNew.nVersion = OVERWINTER_TX_VERSION
     //   txNew.fOverwintered = true
     //   txNew.nVersionGroupId = OVERWINTER_VERSION_GROUP_ID
     //   txNew.nExpiryHeight = <default value>
diff --git a/src/gtest/test_checkblock.cpp b/src/gtest/test_checkblock.cpp
index 225f8ef3b..1c48046ef 100644
--- a/src/gtest/test_checkblock.cpp
+++ b/src/gtest/test_checkblock.cpp
@@ -154,7 +154,7 @@ TEST(ContextualCheckBlock, BlockSproutRulesRejectOverwinterTx) {
     mtx.vout[0].nValue = 0;
 
     mtx.fOverwintered = true;
-    mtx.nVersion = 3;
+    mtx.nVersion = OVERWINTER_TX_VERSION;
     mtx.nVersionGroupId = OVERWINTER_VERSION_GROUP_ID;
 
     CTransaction tx {mtx};
@@ -251,7 +251,7 @@ TEST(ContextualCheckBlock, BlockOverwinterRulesAcceptOverwinterTx) {
         GetBlockSubsidy(1, Params().GetConsensus())/5,
         Params().GetFoundersRewardScriptAtHeight(1)));
     mtx.fOverwintered = true;
-    mtx.nVersion = 3;
+    mtx.nVersion = OVERWINTER_TX_VERSION;
     mtx.nVersionGroupId = OVERWINTER_VERSION_GROUP_ID;
 
     CTransaction tx {mtx};
@@ -350,7 +350,7 @@ TEST(ContextualCheckBlock, BlockSaplingRulesRejectOverwinterTx) {
         GetBlockSubsidy(1, Params().GetConsensus())/5,
         Params().GetFoundersRewardScriptAtHeight(1)));
     mtx.fOverwintered = true;
-    mtx.nVersion = 3;
+    mtx.nVersion = OVERWINTER_TX_VERSION;
     mtx.nVersionGroupId = OVERWINTER_VERSION_GROUP_ID;
 
     CTransaction tx {mtx};
diff --git a/src/gtest/test_checktransaction.cpp b/src/gtest/test_checktransaction.cpp
index bec9cdd6f..d7527dbac 100644
--- a/src/gtest/test_checktransaction.cpp
+++ b/src/gtest/test_checktransaction.cpp
@@ -401,7 +401,7 @@ TEST(checktransaction_tests, non_canonical_ed25519_signature) {
 TEST(checktransaction_tests, OverwinterConstructors) {
     CMutableTransaction mtx;
     mtx.fOverwintered = true;
-    mtx.nVersion = 3;
+    mtx.nVersion = OVERWINTER_TX_VERSION;
     mtx.nVersionGroupId = OVERWINTER_VERSION_GROUP_ID;
     mtx.nExpiryHeight = 20;
 
@@ -432,7 +432,7 @@ TEST(checktransaction_tests, OverwinterConstructors) {
 TEST(checktransaction_tests, OverwinterSerialization) {
     CMutableTransaction mtx;
     mtx.fOverwintered = true;
-    mtx.nVersion = 3;
+    mtx.nVersion = OVERWINTER_TX_VERSION;
     mtx.nVersionGroupId = OVERWINTER_VERSION_GROUP_ID;
     mtx.nExpiryHeight = 99;
 
@@ -496,7 +496,7 @@ TEST(checktransaction_tests, OverwinterValidTx) {
     CMutableTransaction mtx = GetValidTransaction();
     mtx.vjoinsplit.resize(0);
     mtx.fOverwintered = true;
-    mtx.nVersion = 3;
+    mtx.nVersion = OVERWINTER_TX_VERSION;
     mtx.nVersionGroupId = OVERWINTER_VERSION_GROUP_ID;
     mtx.nExpiryHeight = 0;
     CTransaction tx(mtx);
@@ -508,7 +508,7 @@ TEST(checktransaction_tests, OverwinterExpiryHeight) {
     CMutableTransaction mtx = GetValidTransaction();
     mtx.vjoinsplit.resize(0);
     mtx.fOverwintered = true;
-    mtx.nVersion = 3;
+    mtx.nVersion = OVERWINTER_TX_VERSION;
     mtx.nVersionGroupId = OVERWINTER_VERSION_GROUP_ID;
     mtx.nExpiryHeight = 0;
 
@@ -610,7 +610,7 @@ TEST(checktransaction_tests, OverwinterBadVersionGroupId) {
     CMutableTransaction mtx = GetValidTransaction();
     mtx.vjoinsplit.resize(0);
     mtx.fOverwintered = true;
-    mtx.nVersion = 3;
+    mtx.nVersion = OVERWINTER_TX_VERSION;
     mtx.nExpiryHeight = 0;
     mtx.nVersionGroupId = 0x12345678;
 
@@ -626,7 +626,7 @@ TEST(checktransaction_tests, OverwinterNotActive) {
 
     CMutableTransaction mtx = GetValidTransaction();
     mtx.fOverwintered = true;
-    mtx.nVersion = 3;
+    mtx.nVersion = OVERWINTER_TX_VERSION;
     mtx.nVersionGroupId = OVERWINTER_VERSION_GROUP_ID;
     mtx.nExpiryHeight = 0;
 
@@ -643,7 +643,7 @@ TEST(checktransaction_tests, OverwinterFlagNotSet) {
 
     CMutableTransaction mtx = GetValidTransaction();
     mtx.fOverwintered = false;
-    mtx.nVersion = 3;
+    mtx.nVersion = OVERWINTER_TX_VERSION;
     mtx.nVersionGroupId = OVERWINTER_VERSION_GROUP_ID;
     mtx.nExpiryHeight = 0;
 
diff --git a/src/gtest/test_mempool.cpp b/src/gtest/test_mempool.cpp
index 34bc204fa..6ee3eb1b1 100644
--- a/src/gtest/test_mempool.cpp
+++ b/src/gtest/test_mempool.cpp
@@ -169,7 +169,7 @@ TEST(Mempool, OverwinterNotActiveYet) {
     CMutableTransaction mtx = GetValidTransaction();
     mtx.vjoinsplit.resize(0); // no joinsplits
     mtx.fOverwintered = true;
-    mtx.nVersion = 3;
+    mtx.nVersion = OVERWINTER_TX_VERSION;
     mtx.nVersionGroupId = OVERWINTER_VERSION_GROUP_ID;
     mtx.nExpiryHeight = 0;
     CValidationState state1;
diff --git a/src/main.cpp b/src/main.cpp
index 07ed8c592..fb6196c70 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -6058,7 +6058,7 @@ CMutableTransaction CreateNewContextualCMutableTransaction(const Consensus::Para
     if (isOverwintered) {
         mtx.fOverwintered = true;
         mtx.nVersionGroupId = OVERWINTER_VERSION_GROUP_ID;
-        mtx.nVersion = 3;
+        mtx.nVersion = OVERWINTER_TX_VERSION;
         // Expiry height is not set. Only fields required for a parser to treat as a valid Overwinter V3 tx.
 
         // TODO: In future, when moving from Overwinter to Sapling, it will be useful
diff --git a/src/primitives/transaction.h b/src/primitives/transaction.h
index 584a5b7e5..74e76858a 100644
--- a/src/primitives/transaction.h
+++ b/src/primitives/transaction.h
@@ -22,6 +22,13 @@
 #include "zcash/JoinSplit.hpp"
 #include "zcash/Proof.hpp"
 
+// Overwinter transaction version
+static const int32_t OVERWINTER_TX_VERSION = 3;
+static_assert(OVERWINTER_TX_VERSION >= OVERWINTER_MIN_TX_VERSION,
+    "Overwinter tx version must not be lower than minimum");
+static_assert(OVERWINTER_TX_VERSION <= OVERWINTER_MAX_TX_VERSION,
+    "Overwinter tx version must not be higher than maximum");
+
 // Sapling transaction version
 static const int32_t SAPLING_TX_VERSION = 4;
 static_assert(SAPLING_TX_VERSION >= SAPLING_MIN_TX_VERSION,
@@ -585,9 +592,10 @@ public:
             READWRITE(*const_cast<uint32_t*>(&this->nVersionGroupId));
         }
 
-        bool isOverwinterV3 = fOverwintered &&
-                              nVersionGroupId == OVERWINTER_VERSION_GROUP_ID &&
-                              nVersion == 3;
+        bool isOverwinterV3 =
+            fOverwintered &&
+            nVersionGroupId == OVERWINTER_VERSION_GROUP_ID &&
+            nVersion == OVERWINTER_TX_VERSION;
         bool isSaplingV4 =
             fOverwintered &&
             nVersionGroupId == SAPLING_VERSION_GROUP_ID &&
@@ -719,9 +727,10 @@ struct CMutableTransaction
             READWRITE(nVersionGroupId);
         }
 
-        bool isOverwinterV3 = fOverwintered &&
-                              nVersionGroupId == OVERWINTER_VERSION_GROUP_ID &&
-                              nVersion == 3;
+        bool isOverwinterV3 =
+            fOverwintered &&
+            nVersionGroupId == OVERWINTER_VERSION_GROUP_ID &&
+            nVersion == OVERWINTER_TX_VERSION;
         bool isSaplingV4 =
             fOverwintered &&
             nVersionGroupId == SAPLING_VERSION_GROUP_ID &&
diff --git a/src/test/transaction_tests.cpp b/src/test/transaction_tests.cpp
index 094cd5a90..1b0b26ee7 100644
--- a/src/test/transaction_tests.cpp
+++ b/src/test/transaction_tests.cpp
@@ -542,7 +542,7 @@ BOOST_AUTO_TEST_CASE(test_simple_joinsplit_invalidity_driver) {
         CMutableTransaction mtx;
         mtx.fOverwintered = true;
         mtx.nVersionGroupId = OVERWINTER_VERSION_GROUP_ID;
-        mtx.nVersion = 3;
+        mtx.nVersion = OVERWINTER_TX_VERSION;
 
         UpdateNetworkUpgradeParameters(Consensus::UPGRADE_OVERWINTER, Consensus::NetworkUpgrade::ALWAYS_ACTIVE);
         test_simple_joinsplit_invalidity(NetworkUpgradeInfo[Consensus::UPGRADE_OVERWINTER].nBranchId, mtx);
@@ -594,7 +594,7 @@ BOOST_AUTO_TEST_CASE(test_big_overwinter_transaction) {
     uint32_t consensusBranchId = NetworkUpgradeInfo[Consensus::UPGRADE_OVERWINTER].nBranchId;
     CMutableTransaction mtx;
     mtx.fOverwintered = true;
-    mtx.nVersion = 3;
+    mtx.nVersion = OVERWINTER_TX_VERSION;
     mtx.nVersionGroupId = OVERWINTER_VERSION_GROUP_ID;
 
     CKey key;
diff --git a/src/zcbenchmarks.cpp b/src/zcbenchmarks.cpp
index 2c7e99a67..c268e6e12 100644
--- a/src/zcbenchmarks.cpp
+++ b/src/zcbenchmarks.cpp
@@ -243,7 +243,7 @@ double benchmark_large_tx(size_t nInputs)
 
     CMutableTransaction spending_tx;
     spending_tx.fOverwintered = true;
-    spending_tx.nVersion = 3;
+    spending_tx.nVersion = OVERWINTER_TX_VERSION;
     spending_tx.nVersionGroupId = OVERWINTER_VERSION_GROUP_ID;
 
     auto input_hash = orig_tx.GetHash();