diff --git a/src/policy/policy.cpp b/src/policy/policy.cpp
--- a/src/policy/policy.cpp
+++ b/src/policy/policy.cpp
@@ -185,6 +185,7 @@
 
 int64_t GetVirtualTransactionSize(const CTransaction &tx, int64_t nSigOpCost,
                                   unsigned int bytes_per_sigop) {
-    return GetVirtualTransactionSize(::GetSerializeSize(tx, PROTOCOL_VERSION),
-                                     nSigOpCost, bytes_per_sigop);
+    return GetVirtualTransactionSize(
+        ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION), nSigOpCost,
+        bytes_per_sigop);
 }
diff --git a/src/serialize.h b/src/serialize.h
--- a/src/serialize.h
+++ b/src/serialize.h
@@ -53,7 +53,7 @@
     return const_cast<T *>(val);
 }
 
-/*
+/**
  * Lowest-level serialization and conversion.
  * @note Sizes of these types are verified in the tests
  */
@@ -498,7 +498,7 @@
  */
 
 /**
- *  string
+ * string
  */
 template <typename Stream, typename C>
 void Serialize(Stream &os, const std::basic_string<C> &str);
@@ -910,7 +910,7 @@
 }
 
 template <typename T>
-size_t GetSerializeSize(const T &t, int nType, int nVersion = 0) {
+size_t GetSerializeSize(const T &t, int nType, int nVersion) {
     return (CSizeComputer(nType, nVersion) << t).size();
 }
 
diff --git a/src/test/serialize_tests.cpp b/src/test/serialize_tests.cpp
--- a/src/test/serialize_tests.cpp
+++ b/src/test/serialize_tests.cpp
@@ -63,33 +63,33 @@
 };
 
 BOOST_AUTO_TEST_CASE(sizes) {
-    BOOST_CHECK_EQUAL(sizeof(char), GetSerializeSize(char(0), 0));
-    BOOST_CHECK_EQUAL(sizeof(int8_t), GetSerializeSize(int8_t(0), 0));
-    BOOST_CHECK_EQUAL(sizeof(uint8_t), GetSerializeSize(uint8_t(0), 0));
-    BOOST_CHECK_EQUAL(sizeof(int16_t), GetSerializeSize(int16_t(0), 0));
-    BOOST_CHECK_EQUAL(sizeof(uint16_t), GetSerializeSize(uint16_t(0), 0));
-    BOOST_CHECK_EQUAL(sizeof(int32_t), GetSerializeSize(int32_t(0), 0));
-    BOOST_CHECK_EQUAL(sizeof(uint32_t), GetSerializeSize(uint32_t(0), 0));
-    BOOST_CHECK_EQUAL(sizeof(int64_t), GetSerializeSize(int64_t(0), 0));
-    BOOST_CHECK_EQUAL(sizeof(uint64_t), GetSerializeSize(uint64_t(0), 0));
-    BOOST_CHECK_EQUAL(sizeof(float), GetSerializeSize(float(0), 0));
-    BOOST_CHECK_EQUAL(sizeof(double), GetSerializeSize(double(0), 0));
+    BOOST_CHECK_EQUAL(sizeof(char), GetSerializeSize(char(0), 0, 0));
+    BOOST_CHECK_EQUAL(sizeof(int8_t), GetSerializeSize(int8_t(0), 0, 0));
+    BOOST_CHECK_EQUAL(sizeof(uint8_t), GetSerializeSize(uint8_t(0), 0, 0));
+    BOOST_CHECK_EQUAL(sizeof(int16_t), GetSerializeSize(int16_t(0), 0, 0));
+    BOOST_CHECK_EQUAL(sizeof(uint16_t), GetSerializeSize(uint16_t(0), 0, 0));
+    BOOST_CHECK_EQUAL(sizeof(int32_t), GetSerializeSize(int32_t(0), 0, 0));
+    BOOST_CHECK_EQUAL(sizeof(uint32_t), GetSerializeSize(uint32_t(0), 0, 0));
+    BOOST_CHECK_EQUAL(sizeof(int64_t), GetSerializeSize(int64_t(0), 0, 0));
+    BOOST_CHECK_EQUAL(sizeof(uint64_t), GetSerializeSize(uint64_t(0), 0, 0));
+    BOOST_CHECK_EQUAL(sizeof(float), GetSerializeSize(float(0), 0, 0));
+    BOOST_CHECK_EQUAL(sizeof(double), GetSerializeSize(double(0), 0, 0));
     // Bool is serialized as char
-    BOOST_CHECK_EQUAL(sizeof(char), GetSerializeSize(bool(0), 0));
+    BOOST_CHECK_EQUAL(sizeof(char), GetSerializeSize(bool(0), 0, 0));
 
     // Sanity-check GetSerializeSize and c++ type matching
-    BOOST_CHECK_EQUAL(GetSerializeSize(char(0), 0), 1);
-    BOOST_CHECK_EQUAL(GetSerializeSize(int8_t(0), 0), 1);
-    BOOST_CHECK_EQUAL(GetSerializeSize(uint8_t(0), 0), 1);
-    BOOST_CHECK_EQUAL(GetSerializeSize(int16_t(0), 0), 2);
-    BOOST_CHECK_EQUAL(GetSerializeSize(uint16_t(0), 0), 2);
-    BOOST_CHECK_EQUAL(GetSerializeSize(int32_t(0), 0), 4);
-    BOOST_CHECK_EQUAL(GetSerializeSize(uint32_t(0), 0), 4);
-    BOOST_CHECK_EQUAL(GetSerializeSize(int64_t(0), 0), 8);
-    BOOST_CHECK_EQUAL(GetSerializeSize(uint64_t(0), 0), 8);
-    BOOST_CHECK_EQUAL(GetSerializeSize(float(0), 0), 4);
-    BOOST_CHECK_EQUAL(GetSerializeSize(double(0), 0), 8);
-    BOOST_CHECK_EQUAL(GetSerializeSize(bool(0), 0), 1);
+    BOOST_CHECK_EQUAL(GetSerializeSize(char(0), 0, 0), 1);
+    BOOST_CHECK_EQUAL(GetSerializeSize(int8_t(0), 0, 0), 1);
+    BOOST_CHECK_EQUAL(GetSerializeSize(uint8_t(0), 0, 0), 1);
+    BOOST_CHECK_EQUAL(GetSerializeSize(int16_t(0), 0, 0), 2);
+    BOOST_CHECK_EQUAL(GetSerializeSize(uint16_t(0), 0, 0), 2);
+    BOOST_CHECK_EQUAL(GetSerializeSize(int32_t(0), 0, 0), 4);
+    BOOST_CHECK_EQUAL(GetSerializeSize(uint32_t(0), 0, 0), 4);
+    BOOST_CHECK_EQUAL(GetSerializeSize(int64_t(0), 0, 0), 8);
+    BOOST_CHECK_EQUAL(GetSerializeSize(uint64_t(0), 0, 0), 8);
+    BOOST_CHECK_EQUAL(GetSerializeSize(float(0), 0, 0), 4);
+    BOOST_CHECK_EQUAL(GetSerializeSize(double(0), 0, 0), 8);
+    BOOST_CHECK_EQUAL(GetSerializeSize(bool(0), 0, 0), 1);
 }
 
 BOOST_AUTO_TEST_CASE(floats_conversion) {