Organizing Code for a Seamless Transition from C/AL to Extensions in AL: Part 1

Since Business Central 2019 release wave 2 (version 15), the application has become completely AL-based. All functionality that modifies standard business logic must be moved into an Extension. This change influences how upgrades are performed and impacts all the solutions that are still in C/AL, making Dynamics partners consider transitioning to Extensions in AL

Source : 1ClickFactory Blog
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