diff --git a/README.md b/README.md
index 355cd85..f35fd86 100644
--- a/README.md
+++ b/README.md
@@ -161,6 +161,29 @@ CBPurchase.purchaseProduct(purchaseProductParams = purchaseProductParams, custom
  ```
 The above function will handle the purchase against Google Play Store and send the IAP token for server-side token verification to your Chargebee account. Use the Subscription ID returned by the above function, to check for Subscription status on Chargebee and confirm the access - granted or denied.
 
+### Upgrade or Downgrade Product
+Pass the `ChangeProductParams` and `CBCustomer` to the following `ChangeProduct` function when the user chooses the product to purchase.
+
+`CBCustomer` - **Optional object**. Although this is an optional object, we recommend passing the necessary customer details, such as `customerId`, `firstName`, `lastName`, and `email`. This ensures that the customer details in your database match the customer details in Chargebee. If the `customerId` is not passed in the customer's details, then the value of `customerId` will be the same as the `SubscriptionId` created in Chargebee.
+
+**Note**: The `customer` parameter in the below code snippet is an instance of `CBCustomer` class that contains the details of the customer who wants to subscribe or buy the product.
+
+```kotlin
+val changeProductParams = ChangeProductParams(newProductParams, "currentProductId")
+val cbCustomer = CBCustomer("customerId","firstName","lastName","email")
+CBPurchase.changeProduct(changeProductParams = changeProductParams, customer = cbCustomer, object : CBCallback.PurchaseCallback<String>{
+      override fun onSuccess(result: ReceiptDetail, status:Boolean) {
+        Log.i(TAG, "$status")
+        Log.i(TAG, "${result.subscription_id}")
+        Log.i(TAG, "${result.plan_id}")   
+      }
+      override fun onError(error: CBException) {
+        Log.e(TAG, "Error:  ${error.message}")
+      }
+})
+ ```
+The above function is designed to manage subscription upgrades or downgrades between base plans within a single subscription or across different subscriptions.
+
 ### Invoke Manage Subscriptions in your App
 The `showManageSubscriptionsSettings()` function is designed to invoke the Manage Subscriptions in your app using Chargebee's Android SDKs. `Chargebee.showManageSubscriptionsSettings()`, opens the Play Store App subscriptions settings page.
 
diff --git a/app/src/main/java/com/chargebee/example/MainActivity.kt b/app/src/main/java/com/chargebee/example/MainActivity.kt
index a16cc99..5b08607 100644
--- a/app/src/main/java/com/chargebee/example/MainActivity.kt
+++ b/app/src/main/java/com/chargebee/example/MainActivity.kt
@@ -30,6 +30,7 @@ import com.chargebee.example.plan.PlansActivity
 import com.chargebee.example.subscription.SubscriptionActivity
 import com.chargebee.example.token.TokenizeActivity
 import com.chargebee.example.util.CBMenu
+import com.chargebee.example.util.Constants.OLD_PRODUCT_ID
 import com.chargebee.example.util.Constants.PRODUCTS_LIST_KEY
 import com.google.gson.Gson
 import kotlinx.coroutines.CoroutineScope
@@ -133,6 +134,9 @@ class MainActivity : BaseActivity(), ListItemsAdapter.ItemClickListener {
             CBMenu.GetProducts.value -> {
                 getProductIdFromCustomer()
             }
+            CBMenu.ChangeProducts.value -> {
+                getCurrentAndNewProductIdFromCustomer()
+            }
             CBMenu.SubsStatus.value,
             CBMenu.SubsList.value -> {
                 val intent = Intent(this, SubscriptionActivity::class.java)
@@ -152,9 +156,10 @@ class MainActivity : BaseActivity(), ListItemsAdapter.ItemClickListener {
         }
     }
 
-    private fun launchProductDetailsScreen(productDetails: String) {
+    private fun launchProductDetailsScreen(productDetails: String, currentProductId: String? = null) {
         val intent = Intent(this, BillingActivity::class.java)
         intent.putExtra(PRODUCTS_LIST_KEY, productDetails)
+        intent.putExtra(OLD_PRODUCT_ID, currentProductId)
         this.startActivity(intent)
     }
 
@@ -206,7 +211,25 @@ class MainActivity : BaseActivity(), ListItemsAdapter.ItemClickListener {
         dialog.show()
     }
 
-    private fun getProductIdList(productIdList: ArrayList<String>) {
+    private fun getCurrentAndNewProductIdFromCustomer() {
+        val dialog = Dialog(this)
+        dialog.setContentView(R.layout.dialog_input_update_layout)
+        val productIds = dialog.findViewById<View>(R.id.productIdInput) as EditText
+        productIds.hint = "Please enter Product IDs(Comma separated)"
+        val currentProductId = dialog.findViewById<View>(R.id.currentProductIdInput) as EditText
+        currentProductId.hint = "Please enter Current Product ID"
+        val dialogButton = dialog.findViewById<View>(R.id.btn_ok) as Button
+        dialogButton.text = "Submit"
+        dialogButton.setOnClickListener {
+            val productIdList = productIds.text.toString().trim().split(",")
+            val currentProductId = currentProductId.text.toString().trim()
+            getProductIdList(productIdList.toCollection(ArrayList()), currentProductId)
+            dialog.dismiss()
+        }
+        dialog.show()
+    }
+
+    private fun getProductIdList(productIdList: ArrayList<String>, currentProductId: String? = null) {
         CBPurchase.retrieveProducts(
             this,
             productIdList,
@@ -214,7 +237,7 @@ class MainActivity : BaseActivity(), ListItemsAdapter.ItemClickListener {
                 override fun onSuccess(productIDs: ArrayList<CBProduct>) {
                     CoroutineScope(Dispatchers.Main).launch {
                         if (productIDs.size > 0) {
-                            launchProductDetailsScreen(gson.toJson(productIDs))
+                            launchProductDetailsScreen(gson.toJson(productIDs), currentProductId)
                         } else {
                             alertSuccess("Items not available to buy")
                         }
diff --git a/app/src/main/java/com/chargebee/example/billing/BillingActivity.java b/app/src/main/java/com/chargebee/example/billing/BillingActivity.java
index 231ffa4..1879723 100644
--- a/app/src/main/java/com/chargebee/example/billing/BillingActivity.java
+++ b/app/src/main/java/com/chargebee/example/billing/BillingActivity.java
@@ -1,5 +1,6 @@
 package com.chargebee.example.billing;
 
+import static com.chargebee.example.util.Constants.OLD_PRODUCT_ID;
 import static com.chargebee.example.util.Constants.PRODUCTS_LIST_KEY;
 
 import android.app.Dialog;
@@ -17,6 +18,7 @@
 import com.chargebee.android.billingservice.OneTimeProductType;
 import com.chargebee.android.billingservice.ProductType;
 import com.chargebee.android.models.CBProduct;
+import com.chargebee.android.models.ChangeProductParams;
 import com.chargebee.android.models.PurchaseProductParams;
 import com.chargebee.android.network.CBCustomer;
 import com.chargebee.example.BaseActivity;
@@ -35,6 +37,7 @@
 public class BillingActivity extends BaseActivity implements ProductListAdapter.ProductClickListener, ProgressBarListener {
 
     private List<PurchaseProduct> purchaseProducts = null;
+    private String currentProductId = null;
     private ProductListAdapter productListAdapter = null;
     private LinearLayoutManager linearLayoutManager;
     private RecyclerView mItemsRecyclerView = null;
@@ -53,6 +56,7 @@ protected void onCreate(Bundle savedInstanceState) {
 
         mItemsRecyclerView = findViewById(R.id.rv_product_list);
         String productDetails = getIntent().getStringExtra(PRODUCTS_LIST_KEY);
+        this.currentProductId = getIntent().getStringExtra(OLD_PRODUCT_ID);
 
         if(productDetails != null) {
             Gson gson = new Gson();
@@ -163,7 +167,11 @@ private void getCustomerID() {
                     dialog.dismiss();
                 }
             } else {
-                purchaseProduct();
+                if (this.currentProductId != null){
+                    changeProduct();
+                }else {
+                    purchaseProduct();
+                }
                 dialog.dismiss();
             }
         });
@@ -189,6 +197,14 @@ private void purchaseProduct() {
         this.billingViewModel.purchaseProduct(this, purchaseParams, cbCustomer);
     }
 
+    private void changeProduct() {
+        showProgressDialog();
+        PurchaseProduct selectedPurchaseProduct = purchaseProducts.get(position);
+        PurchaseProductParams newProductParams = new PurchaseProductParams(selectedPurchaseProduct.getCbProduct(), selectedPurchaseProduct.getOfferToken());
+        ChangeProductParams changeProductParams = new ChangeProductParams(newProductParams, currentProductId);
+        this.billingViewModel.changeProduct(this, changeProductParams, cbCustomer);
+    }
+
     private void purchaseNonSubscriptionProduct(OneTimeProductType productType) {
         showProgressDialog();
         CBProduct selectedProduct = purchaseProducts.get(position).getCbProduct();
diff --git a/app/src/main/java/com/chargebee/example/billing/BillingViewModel.kt b/app/src/main/java/com/chargebee/example/billing/BillingViewModel.kt
index 1fdf2ee..2e60c84 100644
--- a/app/src/main/java/com/chargebee/example/billing/BillingViewModel.kt
+++ b/app/src/main/java/com/chargebee/example/billing/BillingViewModel.kt
@@ -53,6 +53,31 @@ class BillingViewModel : ViewModel() {
         })
     }
 
+    fun changeProduct(context: Context, changeProductParams: ChangeProductParams, customer: CBCustomer) {
+        // Cache the product id in sharedPreferences and retry validating the receipt if in case server is not responding or no internet connection.
+        sharedPreference =  context.getSharedPreferences("PREFERENCE_NAME",Context.MODE_PRIVATE)
+        CBPurchase.changeProduct(changeProductParams = changeProductParams, customer = customer,  object : CBCallback.PurchaseCallback<String>{
+            override fun onSuccess(result: ReceiptDetail, status:Boolean) {
+                Log.i(TAG, "Subscription ID:  ${result.subscription_id}")
+                Log.i(TAG, "Plan ID:  ${result.plan_id}")
+                productPurchaseResult.postValue(status)
+            }
+            override fun onError(error: CBException) {
+                try {
+                    // Handled server not responding and offline
+                    if (error.httpStatusCode!! in 500..599) {
+                        storeInLocal(changeProductParams.newProductParams.product.id)
+                        validateReceipt(context = context, product = changeProductParams.newProductParams.product)
+                    } else {
+                        cbException.postValue(error)
+                    }
+                } catch (exp: Exception) {
+                    Log.i(TAG, "Exception :${exp.message}")
+                }
+            }
+        })
+    }
+
     private fun validateReceipt(context: Context, product: CBProduct) {
         val customer = CBCustomer(
             id = "sync_receipt_android",
diff --git a/app/src/main/java/com/chargebee/example/util/CBMenu.kt b/app/src/main/java/com/chargebee/example/util/CBMenu.kt
index 777dc73..d372e3d 100644
--- a/app/src/main/java/com/chargebee/example/util/CBMenu.kt
+++ b/app/src/main/java/com/chargebee/example/util/CBMenu.kt
@@ -10,6 +10,7 @@ enum class CBMenu(val value: String) {
     Tokenize("Tokenize"),
     ProductIDs("Get Google Play Product Identifiers"),
     GetProducts("Get Products"),
+    ChangeProducts("Change Product"),
     SubsStatus("Get Subscription Status"),
     SubsList("Get Subscriptions List"),
     GetEntitlements("Get Entitlements"),
diff --git a/app/src/main/java/com/chargebee/example/util/Constants.kt b/app/src/main/java/com/chargebee/example/util/Constants.kt
index 700be5d..a813203 100644
--- a/app/src/main/java/com/chargebee/example/util/Constants.kt
+++ b/app/src/main/java/com/chargebee/example/util/Constants.kt
@@ -2,4 +2,5 @@ package com.chargebee.example.util
 
 object Constants {
     const val PRODUCTS_LIST_KEY = "products"
+    const val OLD_PRODUCT_ID = "currentProductId"
 }
\ No newline at end of file
diff --git a/app/src/main/res/layout/dialog_input_update_layout.xml b/app/src/main/res/layout/dialog_input_update_layout.xml
new file mode 100644
index 0000000..21b4a73
--- /dev/null
+++ b/app/src/main/res/layout/dialog_input_update_layout.xml
@@ -0,0 +1,66 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="300dp"
+    android:layout_height="300dp"
+    tools:context=".MainActivity">
+
+    <com.google.android.material.textfield.TextInputLayout
+        android:id="@+id/planIdInputLayout"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="96dp"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/textView">
+
+        <EditText
+            android:id="@+id/productIdInput"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:ems="13"
+            android:inputType="textPersonName" />
+    </com.google.android.material.textfield.TextInputLayout>
+
+    <com.google.android.material.textfield.TextInputLayout
+        android:id="@+id/currentPlanIdInputLayout"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="20dp"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintHorizontal_bias="0.497"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/textView">
+
+        <EditText
+            android:id="@+id/currentProductIdInput"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:ems="13"
+            android:inputType="textPersonName" />
+    </com.google.android.material.textfield.TextInputLayout>
+
+    <TextView
+        android:id="@+id/textView"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="20dp"
+        android:text="Chargebee"
+        android:textSize="24sp"
+        android:textStyle="bold"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
+
+    <Button
+        android:id="@+id/btn_ok"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="34dp"
+        android:text="Submit"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/planIdInputLayout" />
+
+</androidx.constraintlayout.widget.ConstraintLayout>
\ No newline at end of file
diff --git a/chargebee/src/main/java/com/chargebee/android/billingservice/BillingClientManager.kt b/chargebee/src/main/java/com/chargebee/android/billingservice/BillingClientManager.kt
index a59f2dd..2eb98c5 100644
--- a/chargebee/src/main/java/com/chargebee/android/billingservice/BillingClientManager.kt
+++ b/chargebee/src/main/java/com/chargebee/android/billingservice/BillingClientManager.kt
@@ -13,6 +13,7 @@ import com.chargebee.android.exceptions.CBException
 import com.chargebee.android.exceptions.ChargebeeResult
 import com.chargebee.android.models.CBNonSubscriptionResponse
 import com.chargebee.android.models.CBProduct
+import com.chargebee.android.models.ChangeProductParams
 import com.chargebee.android.models.PricingPhase
 import com.chargebee.android.models.PurchaseProductParams
 import com.chargebee.android.models.PurchaseTransaction
@@ -29,6 +30,7 @@ class BillingClientManager(context: Context) : PurchasesUpdatedListener {
     private var purchaseCallBack: CBCallback.PurchaseCallback<String>? = null
     private val TAG = javaClass.simpleName
     private lateinit var purchaseProductParams: PurchaseProductParams
+    private lateinit var changeProductParams: ChangeProductParams
     private lateinit var restorePurchaseCallBack: CBCallback.RestorePurchaseCallback
     private var oneTimePurchaseCallback: CBCallback.OneTimePurchaseCallback? = null
 
@@ -247,12 +249,135 @@ class BillingClientManager(context: Context) : PurchasesUpdatedListener {
                 } else {
                     oneTimePurchaseCallback?.onError(throwCBException(billingResult))
                 }
+            }
+        }
+
+    }
+
+    internal fun changeProduct(
+        changeProductParams: ChangeProductParams,
+        purchaseCallBack: CBCallback.PurchaseCallback<String>
+    ) {
+        this.purchaseCallBack = purchaseCallBack
+        onConnected({ status ->
+            if (status) {
+                changeProduct(changeProductParams)
+            } else
+                purchaseCallBack.onError(
+                    connectionError
+                )
+        }, { error ->
+            purchaseCallBack.onError(error)
+        })
+
+    }
+
+    /* Update the product: Initiates the billing flow for an change subscription  */
+    private fun changeProduct(changeProductParams: ChangeProductParams) {
+        this.changeProductParams = changeProductParams
+        this.purchaseProductParams = changeProductParams.newProductParams
+        val offerToken = changeProductParams.newProductParams.offerToken
+        val currentProductId = changeProductParams.currentProductId
+        val prorationMode = BillingFlowParams.ProrationMode.IMMEDIATE_WITH_TIME_PRORATION
+
+        if(currentProductId.isEmpty()){
+            val currentProductIdEmptyError = CBException(
+                ErrorDetail(
+                    message = GPErrorCode.CurrentProductIdEmpty.errorMsg,
+                    httpStatusCode = ERROR
+                )
+            )
+            purchaseCallBack?.onError(currentProductIdEmptyError)
+            return
+        }
 
+        val queryProductDetails = arrayListOf(QueryProductDetailsParams.Product.newBuilder()
+            .setProductId(this.purchaseProductParams.product.id)
+            .setProductType(this.purchaseProductParams.product.type.value)
+            .build())
+
+        val productDetailsParams = QueryProductDetailsParams.newBuilder().setProductList(queryProductDetails).build()
+
+        billingClient?.queryProductDetailsAsync(
+            productDetailsParams
+        ) { billingResult, productsDetail ->
+            if (billingResult.responseCode == OK && productsDetail != null) {
+                val productDetailsBuilder = BillingFlowParams.ProductDetailsParams.newBuilder()
+                    .setProductDetails(productsDetail.first())
+                offerToken?.let { productDetailsBuilder.setOfferToken(it) }
+                val productDetailsParamsList =
+                    listOf(productDetailsBuilder.build())
+
+                queryAllSubsPurchaseHistory(ProductType.SUBS.value) { subscriptionHistory ->
+
+                    val billingFlowParams =
+                        BillingFlowParams.newBuilder()
+                            .setProductDetailsParamsList(productDetailsParamsList)
+
+                    if(!isWithinSubscriptionChange(currentProductId)) {
+
+                        val oldPurchaseToken: String = getOldPurchaseToken(subscriptionHistory, currentProductId)
+                        if(oldPurchaseToken.isEmpty()){
+                            val oldPurchaseTokenEmptyError = CBException(
+                                ErrorDetail(
+                                    message = GPErrorCode.OldPurchaseTokenEmpty.errorMsg,
+                                    httpStatusCode = ERROR
+                                )
+                            )
+                            purchaseCallBack?.onError(oldPurchaseTokenEmptyError)
+                        }
+
+                        billingFlowParams.setSubscriptionUpdateParams(
+                            BillingFlowParams.SubscriptionUpdateParams.newBuilder()
+                                .setOldPurchaseToken(oldPurchaseToken)
+                                .setReplaceProrationMode(prorationMode).build()
+                        )
+                    }
+
+                    billingClient?.launchBillingFlow(mContext as Activity, billingFlowParams.build())
+                        .takeIf { billingResult ->
+                            billingResult?.responseCode != OK
+                        }?.let { billingResult ->
+                            Log.e(TAG, "Failed to launch billing flow $billingResult")
+                            val billingError = CBException(
+                                ErrorDetail(
+                                    message = GPErrorCode.LaunchBillingFlowError.errorMsg,
+                                    httpStatusCode = billingResult.responseCode
+                                )
+                            )
+                            purchaseCallBack?.onError(billingError)
+                        }
+                }
+            } else {
+                Log.e(TAG, "Failed to fetch product :" + billingResult.responseCode)
+                purchaseCallBack?.onError(throwCBException(billingResult))
             }
         }
 
     }
 
+    /**
+     * This method determines whether the change is within subscription or not.
+     *
+     * @param [currentProductId] The old/previous product id.
+     */
+    private fun isWithinSubscriptionChange(currentProductId: String): Boolean {
+        return this.purchaseProductParams.product.id == currentProductId
+    }
+
+    /**
+     * This method will return old/previous purchase token.
+     *
+     * @param [subscriptionHistory] The list of previous subscriptions.
+     * @param [currentProductId] The old/previous product id.
+     */
+    private fun getOldPurchaseToken(subscriptionHistory: List<PurchaseTransaction>?, currentProductId: String): String {
+        val purchaseTransactionHistory = mutableListOf<PurchaseTransaction>()
+        purchaseTransactionHistory.addAll(subscriptionHistory ?: emptyList())
+        val prevProduct: PurchaseTransaction? = purchaseTransactionHistory.find { it.productId.first() == currentProductId }
+        return prevProduct?.purchaseToken.orEmpty()
+    }
+
     /**
      * This method will provide all the purchases associated with the current account based on the [includeInActivePurchases] flag set.
      * And the associated purchases will be synced with Chargebee.
@@ -333,15 +458,34 @@ class BillingClientManager(context: Context) : PurchasesUpdatedListener {
 
             else -> {
                 if (purchaseProductParams.product.type == ProductType.SUBS)
-                    purchaseCallBack?.onError(
-                        throwCBException(billingResult)
-                    )
+                    if (this::changeProductParams.isInitialized && this.changeProductParams.currentProductId.isNotEmpty() && billingResult.responseCode == ERROR) {
+                        purchaseCallBack?.onError(
+                            CBException(
+                                ErrorDetail(
+                                    message = GPErrorCode.InactiveProductIdError.errorMsg,
+                                    httpStatusCode = billingResult.responseCode
+                                )
+                            )
+                        )
+                    }
+                    else {
+                        purchaseCallBack?.onError(
+                            throwCBException(billingResult)
+                        )
+                    }
                 else
                     oneTimePurchaseCallback?.onError(
                         throwCBException(billingResult)
                     )
             }
         }
+        if(this::changeProductParams.isInitialized && this.changeProductParams.currentProductId.isNotEmpty()){
+            resetCurrentProductId()
+        }
+    }
+
+    private fun resetCurrentProductId(){
+        this.changeProductParams.currentProductId = ""
     }
 
     /* Acknowledge the Purchases */
diff --git a/chargebee/src/main/java/com/chargebee/android/billingservice/CBPurchase.kt b/chargebee/src/main/java/com/chargebee/android/billingservice/CBPurchase.kt
index 079a2e0..9cd5dc8 100644
--- a/chargebee/src/main/java/com/chargebee/android/billingservice/CBPurchase.kt
+++ b/chargebee/src/main/java/com/chargebee/android/billingservice/CBPurchase.kt
@@ -70,13 +70,36 @@ object CBPurchase {
 
     private fun purchaseProduct(purchaseProductParams: PurchaseProductParams, callback: CBCallback.PurchaseCallback<String>) {
         isSDKKeyValid({
-            log(customer, purchaseProductParams.product.id)
+            log(customer,"buy", purchaseProductParams.product.id, action = "before_purchase_command")
             billingClientManager?.purchase(purchaseProductParams, callback)
         }, {
             callback.onError(it)
         })
     }
 
+    /**
+     * Update Subscription product
+     * @param [changeProductParams] The parameters of the product to be updated.
+     * @param [customer] Optional. Customer Object.
+     * @param [callback] listener will be called when product purchase completes.
+     */
+    fun changeProduct(
+        changeProductParams: ChangeProductParams, customer: CBCustomer? = null,
+        callback: CBCallback.PurchaseCallback<String>
+    ) {
+        this.customer = customer
+        changeProduct(changeProductParams, callback)
+    }
+
+    private fun changeProduct(changeProductParams: ChangeProductParams, callback: CBCallback.PurchaseCallback<String>) {
+        isSDKKeyValid({
+            log(customer,"update", changeProductParams.newProductParams.product.id, changeProductParams.currentProductId, "before_change_product_command")
+            billingClientManager?.changeProduct(changeProductParams, callback)
+        }, {
+            callback.onError(it)
+        })
+    }
+
     /**
      * Buy the non-subscription product with/without customer data
      * @param [product] The product that wish to purchase
@@ -94,7 +117,7 @@ object CBPurchase {
         this.productType = productType
 
         isSDKKeyValid({
-            log(CBPurchase.customer, product.id, productType)
+            log(CBPurchase.customer,"buy", product.id, action = "before_purchase_command", productType = productType)
             billingClientManager?.purchaseNonSubscriptionProduct(product, callback)
         }, {
             callback.onError(it)
@@ -367,17 +390,18 @@ object CBPurchase {
         return billingClientManager as BillingClientManager
     }
 
-    private fun log(customer: CBCustomer?, productId: String, productType: OneTimeProductType? = null) {
-        val additionalInfo = additionalInfo(customer, productId, productType)
+    private fun log(customer: CBCustomer?,name: String, productId: String, currentProductId: String? = null, action:String, productType: OneTimeProductType? = null) {
+        val additionalInfo = additionalInfo(customer, productId, currentProductId, productType)
         val logger = CBLogger(
-            name = "buy",
-            action = "before_purchase_command",
+            name = name,
+            action = action,
             additionalInfo = additionalInfo
         )
         ResultHandler.safeExecute { logger.info() }
     }
-    private fun additionalInfo(customer: CBCustomer?, productId: String, productType: OneTimeProductType? = null): Map<String, String> {
+    private fun additionalInfo(customer: CBCustomer?, productId: String, currentProductId: String?, productType: OneTimeProductType? = null): Map<String, String> {
         val map = mutableMapOf("product" to productId)
+        currentProductId?.let { map["currentProductId"] = (it) }
         customer?.let { map["customerId"] = (it.id ?: "") }
         productType?.let { map["productType"] = it.toString() }
         return map
diff --git a/chargebee/src/main/java/com/chargebee/android/billingservice/GPErrorCode.kt b/chargebee/src/main/java/com/chargebee/android/billingservice/GPErrorCode.kt
index c643653..5bbebb5 100644
--- a/chargebee/src/main/java/com/chargebee/android/billingservice/GPErrorCode.kt
+++ b/chargebee/src/main/java/com/chargebee/android/billingservice/GPErrorCode.kt
@@ -24,6 +24,9 @@ enum class GPErrorCode(val errorMsg: String) {
     BillingClientNotReady("Play services not available"),
     SDKKeyNotAvailable("SDK key not available to proceed purchase"),
     InvalidPurchaseToken("The Token data sent is not correct or Google service is temporarily down"),
+    InactiveProductIdError("Unable to complete the purchase, Check if active currentProductId is passed and try again"),
+    OldPurchaseTokenEmpty("There is no active subscription present for the given product ID. Please verify if it's a valid ID and try again"),
+    CurrentProductIdEmpty("The current product ID is empty. Please try again with a valid ID"),
 }
 
 internal enum class BillingErrorCode(val code: Int, val message: String) {
diff --git a/chargebee/src/main/java/com/chargebee/android/models/ChangeProductParams.kt b/chargebee/src/main/java/com/chargebee/android/models/ChangeProductParams.kt
new file mode 100644
index 0000000..b2d0e29
--- /dev/null
+++ b/chargebee/src/main/java/com/chargebee/android/models/ChangeProductParams.kt
@@ -0,0 +1,6 @@
+package com.chargebee.android.models
+
+data class ChangeProductParams(
+    val newProductParams: PurchaseProductParams,
+    var currentProductId: String
+)
\ No newline at end of file