prDS CWA 17852:2025

Extensions for Financial Services (XFS) - XFS4IoT Specification - 2024-03 Release

Scope

XFS4IoT has been identified as a successor to XFS 3.x to meet the following requirements:
1. Replace the XFS and J/XFS standards in the marketplace.
2. Target industries - Retail Banking.
3. Operating System Agnostic and Technology and Language Adaptable.
4. Multi-Vendor - Able to run common core high level functionality on multiple vendors hardware, while providing access to finer level device API granularity.
5. Flexibility - enabling new hardware topologies, device types and functionality to be rapidly adapted.
6. Support end to end application level security.
7. Should not prevent the use of a low resource computing environment.
8. Provide a good developer experience by providing a well-documented API that is easy to learn, is quick to market and reduces risk by exposing an unambiguous interface.
9. Leverage existing standards.
Within the overall requirements specified in the Charter, the opportunity has been taken to solve some of the issues with the 3.x interface while retaining all the same functionality:
1. Binary data structures makes adding new functionality difficult due to compatibility issues, leading to multiple redundant versions of the same command appearing in many of the existing device classes. To resolve this, a flexible text based approach has been adopted including the wide use of default parameters.
2. Compound devices have been difficult for applications to implement, particularly cash recycling. Addition of other shared functionality such as end to end security would make the use of compound devices more prevalent. Compound devices are removed in XFS4IoT, a single Service can support as many interfaces as required to support its requirements.
Migration from and to 3.x is a major consideration to support adoption of XFS4IoT. While a lot of duplication has been removed (for example the Card Reader interface has fewer commands and events defined than the equivalent 3.x IDC specification), all the same IDC commands and events can be implemented. In some cases, this is achieved by having shared common commands such as Common.Status which replaces all the 3.x WFS_INF_XXX_STATUS commands.