AL Interfaces with Default Implementations
One of the most significant architectural improvements in Business Central 29 is the ability to add default method implementations to AL interfaces. This seemingly simple feature unlocks powerful patterns for managing complex extension architectures, particularly when you're building platform-level solutions or managing multiple interdependent extensions.
Before BC29, interfaces were immutable once created. Adding a new method meant every implementing class would break until it provided an implementation. In multi-extension ecosystems, this was a maintenance nightmare. BC29 changes this fundamentally.