diff --git a/src/main/java/com/algorand/algosdk/transaction/Transaction.java b/src/main/java/com/algorand/algosdk/transaction/Transaction.java
index c352b0f39..6078c9e5d 100644
--- a/src/main/java/com/algorand/algosdk/transaction/Transaction.java
+++ b/src/main/java/com/algorand/algosdk/transaction/Transaction.java
@@ -302,7 +302,6 @@ public static Transaction createPaymentTransaction(Address sender, BigInteger fe
                 null,
                 null,
                 null,
-                null,
                 null);
     }
 
@@ -407,7 +406,6 @@ public static Transaction createKeyRegistrationTransaction(Address sender, BigIn
                 null,
                 null,
                 null,
-                null,
                 null);
     }
 
@@ -535,7 +533,6 @@ public static Transaction createAssetCreateTransaction(Address sender, BigIntege
                 null,
                 null,
                 null,
-                null,
                 null);
     }
 
@@ -737,13 +734,16 @@ private Transaction(@JsonProperty("type") Type type,
                 convertToAddressList(accounts),
                 foreignApps,
                 foreignAssets,
-                boxReferences,
                 globalStateSchema,
                 applicationId,
                 localStateSchema,
                 clearStateProgram == null ? null : new TEALProgram(clearStateProgram),
                 extraPages
         );
+        // Set fields _not_ exposed by public constructor.  Needed because:
+        // * Adding parameters to a public constructor is a breaking API change.
+        // * To ensure JSON/msgpack serialization (via Jackson's ObjectMapper) works, must add `@JsonProperty` to _a_ constructor.  Using a private constructor here to maintain API backwards compatibility.
+        if (boxReferences != null) this.boxReferences = boxReferences;
     }
 
     /**
@@ -795,7 +795,6 @@ public Transaction(
             List<Address> accounts,
             List<Long> foreignApps,
             List<Long> foreignAssets,
-            List<BoxReference> boxReferences,
             StateSchema globalStateSchema,
             Long applicationId,
             StateSchema localStateSchema,
@@ -846,7 +845,6 @@ public Transaction(
                 accounts,
                 foreignApps,
                 foreignAssets,
-                boxReferences,
                 globalStateSchema,
                 applicationId,
                 localStateSchema,
@@ -905,7 +903,6 @@ public Transaction(
             List<Address> accounts,
             List<Long> foreignApps,
             List<Long> foreignAssets,
-            List<BoxReference> boxReferences,
             StateSchema globalStateSchema,
             Long applicationId,
             StateSchema localStateSchema,
@@ -949,7 +946,6 @@ public Transaction(
         if (accounts != null) this.accounts = accounts;
         if (foreignApps != null) this.foreignApps = foreignApps;
         if (foreignAssets != null) this.foreignAssets = foreignAssets;
-        if (boxReferences != null) this.boxReferences = boxReferences;
         if (globalStateSchema != null) this.globalStateSchema = globalStateSchema;
         if (applicationId != null) this.applicationId = applicationId;
         if (localStateSchema != null) this.localStateSchema = globalStateSchema;