Evolve AL interfaces with default implementations

Development: Evolve AL interfaces with default implementations. Generally available, GA 2026-10 (Microsoft 365 roadmap). "Add default method bodies to AL interfaces so existing implementors continue working, then use RequiredPending and analyzer rules to introduce required methods safely. Business value: Extension publishers can add behavior to an interface without immediately requiring every implementing extension to change.

Microsoft 365 roadmap 573352 · Development · generally available · roadmap status “Launched”, phase General Availability

What Microsoft says

“Add default method bodies to AL interfaces so existing implementors continue working, then use RequiredPending and analyzer rules to introduce required methods safely. Business value: Extension publishers can add behavior to an interface without immediately requiring every implementing extension to change. Default methods provide a compatible implementation, while the new transition attribute and AppSourceCop rules support a managed path toward making a method mandatory in a future version. This reduces disruptive interface upgrades and gives dependent developers time to adopt new contracts.”

Dates

General availability: October CY2026 (2026 release wave 2)
Public preview: not given
On the roadmap since 2026-09-30, last changed 2026-09-30

Covered by

Matched by Haiku among videos and Learn pages in the same galaxy system, checked against the roadmap ids and the evidence text. Every link below was reviewed by Opus.

Videos

What’s new in AL and Tools (2026 release wave 2): Interface default implementations at 7:38
Business Central 29 0 Default Implementations in AL Interfaces: Default implementation for AL interfaces at 4:14; Required pending attribute for AL interface methods at 8:52
Microsoft presents: Building and shipping agents in Business Central: Optional interface methods at 23:50

Microsoft Learn

Source: Microsoft 365 roadmap. Status words follow the roadmap.