# Release History source: https://developer.mastercard.com/unified-installments/documentation/release-history/index.md This page summarizes the history of the Mastercard Installments API Program from the year 2022 forward. Details of changes based on each release are mentioned in the table. Notable changes are as follows (in reverse chronological order). | **Release Dates** | **Release Version** | **Description** | |-------------------|---------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | September 2022 | v1.0 | Launched the Mastercard Installments Merchant Participation API to provide merchant opt-out information to the Installments Program Provider. | | October 2022 | v1.1 | Launched the Mastercard Installments APIs relevant to the Offers Delivered at Merchant Checkout use case. | | April 2023 | v2.1.0 | Updated the Mastercard Installments Merchant Participation API to include merchant's opt-in/opt-out information with prepaid products. Also, that are market-specific to the Installments Program Provider. | | May 2023 | v2.2.0 | Updated Mastercard Installments Merchant participation documentation to include the desired merchant opt-in support changes for non-bilateral product codes. Also, the wallet field will not ever appear if it has no data to be passed. If an IPP is not configured to receive any wallet details, hence that field is suppressed in the response to adhere to the best API standards. | | February 2024 | v4.0.2 | Added capability for Merchant participation API to allow MID merchant participation submission by Acquirer and query on its status of processing from Mastercard alongside IPP being able to retrieve all MID and MAID (non)participating merchants info through API. | | June 2024 | v5.1.0 | Added a new product named Mastercard Installments Payment Services solution that enables issuers to present installments offers to their cardholders with an existing line of credit during checkout or post the purchase. Four new API endpoints have been added, such as `POST /offers`, `POST /plans`, `POST /consumers/pans/registrations`, and `POST /consumers/pans/deregistrations`. | | August 2024 | v7.0.1 | * **Enhanced Merchant Participation API**: Expanded API capabilities to include support for GCS product code and Merchant Group specifically for the Australian market. This strategic enhancement empowers acquirers to onboard MID merchants with differentiated pricing structures aligned with Mastercard agreements. * **Improved Field Naming** : Renamed the `nonMerchantNegotiatedParticipation` field to `optIn` for improved clarity and ease of understanding, while maintaining backward compatibility. * **New Search Endpoint**: Introduced the POST /merchants/searches endpoint, simplifying merchant and participation data retrieval for acquirers based on various search criteria. * **Removed Encryption Support**: Eliminated encryption support in the MP API, aligning with the updated data classification of PII information as restricted (formerly confidential), thereby removing the necessity for encryption in specific markets. | | September 2024 | v8.0.0 | * Changes to /plans and POST /offers API specification, to move merchant name field from `sensitiveData` to merchant object. * Added documentation and specification for `POST /notifications` outbound API. * Updated integration guide to reflect the above changes. | | October 2024 | v8.0.1 | Enhanced [Integration and Testing guide](https://developer.mastercard.com/unified-installments/tutorial/integration-and-testing/index.md) to describe payload encryption for every API endpoint clearly, along with a few minor documentation fixes. | | October 2024 | v8.0.2 | * Enhanced [API Basics](https://developer.mastercard.com/unified-installments/documentation/api-reference/mastercard-installments-services/index.md) page to elaborate payload encryption requirements * Added [Test Cases](https://developer.mastercard.com/unified-installments/documentation/testing/mastercard-installments-payment-services/installments-notification-api/index.md) for Notification API * Updated the [API specification](https://developer.mastercard.com/unified-installments/documentation/api-reference/mastercard-installments-services/inbound-api/index.md#api) with the following changes. * Added a new parameter `transactionOffers` in `POST /plans` and `POST /notifications` API request payload. * Added two new parameters in the `POST /notifications` API request payload, `issuerCid` and `issuerIca`. * Updated `maxLength` for `offerId` from 8 to 64 in `POST /plans` and `POST /notifications` endpoints. Note: The changes are already made on the Sandbox environment and will be available on the production environment on 14 November 2024. | | November 2024 | v8.0.3 | Improvised [Postman Collection](https://developer.mastercard.com/unified-installments/documentation/postman-collection/index.md) page to describe how to setup and configure the Postman in order to integrate and test the Mastercard Installments API. | | November 2024 | v9.0.0 | * **MAID MP submission / retrieval through the MP API** : Added capability for [Merchant participation API](https://developer.mastercard.com/unified-installments/documentation/api-reference/mastercard-installments-services/inbound-api/index.md#api) to allow MAID merchant participation submission by the Acquirer and query on its status of processing from Mastercard. * **The IPP can search MP by Merchants** : In addition to the Acquirer, IPP will also be able to search merchant participation information by passing merchant name using `POST /merchants/searches`. * **Removed Bilateral product code** list and Bilateral product merchant participation details as they are not being supported anymore for now. | | February 2025 | v9.1.0 | 1. Added a new validation to restrict usage of special characters, such as pipe separated character, backtick, ", \<, \>, (, ), {}, \[\], !, %, $, #, /, :, ;, \^ for `merchantLegalName` and `address` parameters across all Merchant Participation APIs. If a customer uses any of these characters in the request, the request will fail with a validation error indicating the same. Refer to the [API Reference](https://developer.mastercard.com/unified-installments/documentation/api-reference/mastercard-installments-services/inbound-api/index.md#api) page for the following endpoints: * `POST /merchants/mids/searches` - Request param * `POST /merchants/searches` - Request param * `POST /merchants/participations` - Request param * `GET /merchants/participations` - Response param 2. Added two new tests under [Merchant Participation API Testing](https://developer.mastercard.com/unified-installments/documentation/testing/merchant-participation-api/merchant-participation-api-positivesc/index.md) page. 3. Added a new page [Test Data for Mastercard Installments Payment Services](https://developer.mastercard.com/unified-installments/documentation/testing/mastercard-installments-payment-services/index.md), under [Testing](https://developer.mastercard.com/unified-installments/documentation/testing/index.md) page. 4. Added details of payload encryption for `GET /plans/{plan_id}` endpoint under [Encryption](https://developer.mastercard.com/unified-installments/documentation/api-reference/mastercard-installments-services/inbound-api/index.md#encryption) page. | | April 2025 | v9.1.1 | 1. `acquirerId` data type changed from string to number to support 4-11 digits in `POST /offers` endpoint. 2. Added `tokenTransactionId` and `transactionLinkId` in the `POST /plans request`. Corresponding examples and error messages for these fields are added. 3. Added `offerCode`, `tokenTransactionId` and `transactionLinkId` in `POST /notifications` request. 4. Improved Zally score 5. Following sections are updated: * [Merchant participation API](https://developer.mastercard.com/unified-installments/documentation/api-reference/mastercard-installments-services/inbound-api/index.md#api) * [Reference Application](https://developer.mastercard.com/unified-installments/documentation/reference-app/index.md) * [Import Mastercard Installments Collection](https://developer.mastercard.com/unified-installments/tutorial/integration-and-testing/step1/) | | August 2025 | v9.1.2 | Introduced a new endpoint to fetch real-time offers from Issuers. Additionally, enhanced and aligned the eligible offer response to simplify the fee field. Note: The changes are already made in the Sandbox environment and will be available on the production environment on 4th September 2025. | | August 2025 | v9.1.3 | Made multiple changes in Installment Plan API POST endpoint. 1. The following fields are mandatory in the request: * `offerId` * `consumer.primaryAccountNumber` * `planInstallmentInformation.currency` * `planInstallmentInformation.frequency` * `planInstallmentInformation.otherInstallmentAmount` * planInstallmentInformation.tenure 2. The following fields will be conditional. One of them will have to be present in the Request of POST /plans endpoint * `offerTransactionId` * `distributionpartnerTransactionId` 3. Rest all the fields are marked optional. 4. A new field `partnerInstallmentLink` is added in the response of POST /plans. This is an optional field and will only be available in the response if configured, else field will not be visible. Note: The changes are already made on the Sandbox environment and will be available on the production environment on 18th September 2025. | | February 2026 | v9.1.4 | Updated the following information: * Updated the validation to restrict usage of special characters for `merchantLegalName` and `address` parameters to improve accuracy and compliance in `POST /merchants/participations` - Request param of Merchant Participation API. * Regex rules have been relaxed to allow broader character support while still preventing invalid or malicious inputs. The reference application has been updated to reflect these changes, ensuring consistency across onboarding workflows. | | March 2026 | v9.1.4 | * Renamed these products as a part of rebranding: * Mastercard Installments Program with Merchant Participation as **Mastercard Installments Credential** * Mastercard Installments Payment Services as **Mastercard Installments Services** * Segregated APIs as inbound and outbound APIs under the **Mastercard Installments API** . All inbound APIs are added under **Inbound APIs** and all outbound APIs are added under **Outbound APIs** . Note: These are just segregation of the APIs and no functionality or field level changes are done. | Refer to the [Use Cases](https://developer.mastercard.com/unified-installments/documentation/use-cases/mastercard-installments-program-with-merchant-participation/index.md) section for a functional explanation and the [API Reference](https://developer.mastercard.com/unified-installments/documentation/api-reference/mastercard-installments-services/index.md#apis). Section for technical details of new APIs.