# Release History
source: https://developer.mastercard.com/user-account-management-service/documentation/release-history/index.md

## Release History {#release-history}

This section contains a history of what has been implemented in the User Account Management API.

Following are the list of changes (in reverse chronological order).

| **Release Dates** | **Release Version** |                                                                                                                                                                                                                                                                                                                          **Description**                                                                                                                                                                                                                                                                                                                          |
|-------------------|---------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| September 2023    | v5.0                | Introduced the ability to filter the accounts based on the programIdentifier through the [Lookup Identifiers](https://developer.mastercard.com/user-account-management-service/documentation/use-cases/lookup-identifiers/index.md) endpoint. Introduced the ability to verify a user based on answers to the security questions through the [Verify User](https://developer.mastercard.com/user-account-management-service/documentation/use-cases/user-management/index.md#verify-user) endpoint.                                                                                                                                                               |
| August 2023       | v4.1                | Added User-Defined Fields (UDFs) 2, 3, and 4 for the [POST /users](https://developer.mastercard.com/user-account-management-service/documentation/use-cases/user-management/index.md#enroll-user) endpoint. Updated the [Lookup Identifiers](https://developer.mastercard.com/user-account-management-service/documentation/use-cases/lookup-identifiers/index.md) capability to return an array of sensitive identifiers like BAN and BCN in the response. Added the PCLOUser object response for the [Retrieve User](https://developer.mastercard.com/user-account-management-service/documentation/use-cases/user-management/index.md#retrieve-user) endpoint. |
| July 2023         | v4.0                | Expanded the [Lookup Identifiers](https://developer.mastercard.com/user-account-management-service/documentation/use-cases/lookup-identifiers/index.md) capability to return sensitive identifiers like BAN and BCN in the response. Certain services require different token identifiers to complete a function (such as requesting a lost or stolen card). This section documents how to exchange sensitive identifiers with their token counterparts, and vice versa. Introduced offset based pagination. API performance improvements.                                                                                                                        |
| May 2023          | v3.1                | Updated Primary flags in [Account Groups](https://developer.mastercard.com/user-account-management-service/documentation/use-cases/account-management/index.md#group-accounts). This change allows an account to be moved to another household and updates the primary flag for both households, enforcing only one primary account in the household. Minor bug fix for User-Defined Fields (UDFs) for the [PUT /accounts](https://developer.mastercard.com/user-account-management-service/documentation/use-cases/account-management/index.md#update-account) endpoint.                                                                                         |
| April 2023        | v3.0                | Introduced the ability to group accounts into households through the [Account Groups](https://developer.mastercard.com/user-account-management-service/documentation/use-cases/account-management/index.md#group-accounts) endpoint.                                                                                                                                                                                                                                                                                                                                                                                                                              |
| March 2023        | v2.0                | Introduced customer validation and validation questions through the [Retrieve User](https://developer.mastercard.com/user-account-management-service/documentation/use-cases/user-management/index.md#retrieve-user) endpoint.                                                                                                                                                                                                                                                                                                                                                                                                                                    |
| February 2023     | v1.0                | Initial publication of the User Account Management to Mastercard Developers.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |

Refer to the [Use cases](https://developer.mastercard.com/user-account-management-service/documentation/use-cases/index.md) section for a functional explanation and the [API Reference](https://developer.mastercard.com/user-account-management-service/documentation/api-reference/index.md) section for technical details.