To ensure legacy C2 CIS applications are able to support MDO and DT requirements, this LoE will ensure inclusion of requirements to adapt and digitise legacy/ongoing domain-specific C2 CIS programmes, for example, to enable online analytical processing, data transaction processing, geospatial services, and cross-domain C2 and information exchange. These requirements could include implementing Web Service Interfaces through integration of Application Programming Interfaces (API) (as recommended in AC/322-WP(2022)0059-REV2). This may also include requirements to transition into cloud-native applications, to support the Multi-JOA C2 Environment Strategy, and to be interoperable within the Digital Backbone. These should be done in coordination and aligned with the CDP LoE, and the delivery of these requirements will be facilitated by providing ad-hoc testing and experimentation in digitised environments.