# December 2026 Pre-Release Notes
source: https://developer.mastercard.com/mdes-pre-digitization/documentation/pre-release-notes/prereleasenote_nse_dec26/index.md

MDES is enhancing the Pre-Digitization API to notify issuers of token-related suspicious transaction activity identified during token authorization processing.
This enhancement extends the existing capability that already sends suspicious event notifications for wallet-initiated replenishments.

By extending these alerts across additional token lifecycle events, issuers can better identify potential fraud and token misuse, enabling more effective monitoring and risk management throughout the token lifecycle.

### Impacted APIs: {#impacted-apis}

* Notify Suspicious Events (NSE)

## Release Dates {#release-dates}

* MTF - 18 November 2026
* Production - 2 December 2026

### Impacted Market {#impacted-market}

* Availability: Global

## Change 1 Introduction of Transactions event {#change-1-introduction-of-transactions-event}

* A new event has been added to the list of suspicious activity events associated to a token's transaction.

|                                                                                                                                                                             Field and Description                                                                                                                                                                             | Data Type | Min Length | Max Length | Required |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------|------------|------------|----------|
| `eventName` The name of the suspicious event. Possible values are: * REPLENISH - Suspicious ATC values were reported during replenishment. * **TRANSACTIONS** - Suspicious transactions were detected for the token such as excessive replay attempts or a high number of invalid cryptograms. Further transaction details is provided in the `transactionDetails` parameter. | String    | 1          | 32         | Yes      |

* Added `transactionDetails` parameter that provides information about suspicious transaction incidents reported by the authorization network for a token.

|                                                                                                                                                                                                                                                                                                                                                                                                                                                                               Field and Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |    Data Type    | Min Length | Max Length |                         Required                          |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------|------------|------------|-----------------------------------------------------------|
| `transactionDetails` The suspicious transaction incidents reported by the authorization network for a token. New values can be added at any time and must be accepted without prior notice. Possible values are: * **REPLAY** - Excessive replay transactions detected (the same cryptogram was received more than once). * **REPLAY_VELOCITY** - Excessive replay transactions detected within a limited period of time (NODES transactions only) where the same cryptogram was received more than once. * **INVALID_CRYPTOGRAM** - Excessive transactions with an invalid cryptogram. * **INVALID_CRYPTOGRAM_VELOCITY** - Excessive transactions with an invalid cryptogram detected within a limited period of time (NODES transactions only). * **INVALID_ATC** - Excessive transactions with an invalid ATC or an ATC outside the accepted range. * **MISC_ERRORS** - Excessive errors of various types including replay transactions, invalid cryptograms, and invalid ATCs. | Array\[String\] | 1          | 36         | Conditional -- required if `eventName` is `TRANSACTIONS`. |


API Reference: `GET /notifySuspiciousEvents`

## Impact {#impact}

### Existing Customers {#existing-customers}

Existing issuers that support the Notify Suspicious Events API will automatically receive Transactions event notifications. Issuers that do not want to receive these notifications may opt-out by contacting their Mastercard representative.

### New Customers {#new-customers}

Issuers can opt-in to receive the Transactions event notifications through the MDES Manager application by enabling the Notify Suspicious Events API check box in their Message Profile. Issuers that enable this check box must be prepared to receive both Transactions and Replenish event notifications. By default, these notifications are disabled.

### Personal data \& Privacy Note {#personal-data--privacy-note}

Issuers are reminded that the information presented via the Pre-Digitization API includes personal data which is subject to data privacy laws. Issuers must satisfy themselves that the processing of such personal data is compliant with applicable privacy laws