diff --git a/package-lock.json b/package-lock.json
index ea89e7e..a9ed162 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "scryptlib",
-  "version": "2.1.37",
+  "version": "2.1.38",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "scryptlib",
-      "version": "2.1.37",
+      "version": "2.1.38",
       "hasInstallScript": true,
       "license": "MIT",
       "dependencies": {
diff --git a/package.json b/package.json
index 2b2755b..d64beb6 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "scryptlib",
-  "version": "2.1.37",
+  "version": "2.1.38",
   "description": "Javascript SDK for integration of Bitcoin SV Smart Contracts written in sCrypt language.",
   "engines": {
     "node": ">=14.0.0"
diff --git a/patches/bsv/index.d.ts b/patches/bsv/index.d.ts
index 463de3b..fb49be1 100644
--- a/patches/bsv/index.d.ts
+++ b/patches/bsv/index.d.ts
@@ -929,6 +929,7 @@ declare module 'bsv' {
             outputScript?: Script | string,
             satoshis?: number
         ): this;
+        removeInput(txId: string, outputIndex: number): void;
         addOutput(output: Transaction.Output): this;
         addData(value: Buffer | string): this;
         lockUntilDate(time: Date | number): this;
@@ -958,9 +959,7 @@ declare module 'bsv' {
 
         getSerializationError(opts?: object): any;
 
-        _getUnspentValue(): number;
-        _estimateFee(): number;
-        _estimateSize: number;
+        getUnspentValue(): number;
         setInputScript(inputIndex: number | {
             inputIndex: number,
             privateKey?: PrivateKey | Array<PrivateKey>,
@@ -978,6 +977,7 @@ declare module 'bsv' {
         sealAsync(): Promise<this>;
         isSealed(): boolean;
         getChangeAmount(): number;
+        getEstimateSize(): number;
         getEstimateFee(): number;
         checkFeeRate(feePerKb?: number): boolean;
         prevouts(): string;
diff --git a/patches/bsv/lib/bn.js b/patches/bsv/lib/bn.js
index 87d6528..1874343 100644
--- a/patches/bsv/lib/bn.js
+++ b/patches/bsv/lib/bn.js
@@ -50,7 +50,7 @@
 
   var Buffer
   try {
-    Buffer = require('buffer').Buffer
+    Buffer = require('buffer/').Buffer
   } catch (e) {
   }
 
diff --git a/patches/bsv/lib/transaction/transaction.js b/patches/bsv/lib/transaction/transaction.js
index 978f7eb..e35c7d5 100644
--- a/patches/bsv/lib/transaction/transaction.js
+++ b/patches/bsv/lib/transaction/transaction.js
@@ -202,7 +202,7 @@ Transaction.prototype.getSerializationError = function (opts) {
     return new errors.Transaction.InvalidSatoshis()
   }
 
-  var unspent = this._getUnspentValue()
+  var unspent = this.getUnspentValue()
   var unspentError
   if (unspent < 0) {
     if (!opts.disableMoreOutputThanInput) {
@@ -876,7 +876,7 @@ Transaction.prototype._updateChangeOutput = function () {
     script: this._changeScript,
     satoshis: 0
   }))
-  var available = this._getUnspentValue()
+  var available = this.getUnspentValue()
   var fee = this.getFee()
   var changeAmount = available - fee
   this._removeOutput(this._changeIndex)
@@ -917,7 +917,7 @@ Transaction.prototype.getFee = function () {
   }
   // if no change output is set, fees should equal all the unspent amount
   if (!this._changeScript) {
-    return this._getUnspentValue()
+    return this.getUnspentValue()
   }
   return this._estimateFee()
 }
@@ -930,7 +930,7 @@ Transaction.prototype._estimateFee = function () {
   return Math.ceil(estimatedSize / 1000 * (this._feePerKb || Transaction.FEE_PER_KB))
 }
 
-Transaction.prototype._getUnspentValue = function () {
+Transaction.prototype.getUnspentValue = function () {
   return this._getInputAmount() - this._getOutputAmount()
 }
 
@@ -951,6 +951,10 @@ Transaction.prototype._clearSignatures = function () {
 //      ???     script
 //
 // 4    locktime
+Transaction.prototype.getEstimateSize = function () {
+  return this._estimateSize()
+}
+
 Transaction.prototype._estimateSize = function () {
   var result = 4 + 4 // size of version + size of locktime
   result += Varint(this.inputs.length).toBuffer().length
@@ -1439,7 +1443,7 @@ Transaction.prototype.getEstimateFee = function () {
  * @returns true or false
  */
 Transaction.prototype.checkFeeRate = function (feePerKb) {
-  var fee = this._getUnspentValue()
+  var fee = this.getUnspentValue()
 
   var estimatedSize = this._estimateSize()
   var expectedRate = (feePerKb || this._feePerKb || Transaction.FEE_PER_KB) / 1000