Background

An incremental schema change to the Whisperer API is scheduled for 01 September 2025, introducing:

• Support for client-specified Pegged order offset types
• Support for ExecutionReport restatements of long-lived orders and other venue-specific scenarios.
• inclusion of all originating order parameters in the ExecutionReport message, to facilitate workflow and analytics use cases.
• A new TimeInForce value, GFS ("Good For Session"), to support venues such as EBS.

This schema change is a preparatory and backwardly compatible step with no functional impact.

Individual venue changes to implement the new fields and functionality will be introduced in subsequent releases.

Affected Venues

This change will apply to all venue trading sessions, since the above changes affect the following messages:

• NewOrderMultileg
• MultilegOrderCancelReplaceRequest
• ExecutionReport

Change

An incremental and backwardly compatible version change (v19458) will be deployed through all UAT and PROD environments.

Details of the changes are documented in the pages below:

• SBE Schema
• FIX Protocol

Timeline

• 01 September 2025 - UAT - Whisperer API Schema version 19458 will be available for clients. Whisperer Enterprise release 2025.08.29.WE will be deployed to client UAT environments.
• At client discretion - PROD - Clients requiring the new features should contact the MarketFactory Delivery Team to ensure they are upgraded to Whisperer Enterprise release 2025.08.29.WE or later.

Whisperer clients who have implemented Template Extension will not need to make any changes until they choose to consume or publish the new fields and enum values.

After upgrade, Clients should expect to consume/publish new fields and enumeration values in the following messages:

• NewOrderMultileg
• MultilegOrderCancelReplaceRequest
• ExecutionReport