As we learned that there are two approaches of customization in Dynamics 365 for Finance and Operations, Enterprise edition, however Microsoft is going to restrict overlayering and allow only extension for customization. Reason is very obvious, being in the cloud Microsoft wants to enable continuous update and want to get Dynamics 365 for Finance and Operations, Enterprise edition closer to SaaS offering. By eliminating the overlayering in the models which Microsoft ships as part of the project, Microsoft will be able to deliver application hot fixes and new feature updates and customer can uptake those features and hotfixes with very little or no effort.
The following diagram represents the goal and objective of sealing the model for overlayering:
To eliminate overlayering, the following two new concepts are introduced in the product model:
- Soft seal: If a model is soft sealed, you will get compile time warning on overlayer of that model. You can still build the solution and use it but it’s a warning to get prepared to replace your overlayered code with extensions.
- Hard seal: If a model is hard sealed, overlayering not allowed at design time and/or during implementation configuration. After Nov 2016 release, platform and foundation layers are hard sealed which means you can not overlayer those models.
The following image shows the roadmap shared by the product team on sealing the remaining models:
As shown in the diagram, application platform and application foundation models are already hard sealed with Nov 2016 updates. Application suite core models such as directory, dimension, case, and so on will be Soft sealed by Spring release of 2017 and hard sealed in Fall release 2017. Application suite which is the biggest model and contain most of the application functionality will be soft sealed by Fall release 2017 and hard sealed in spring release of 2018. This means if you use Spring release of 2018, you will not be able to overlayer any code shipped by Microsoft. Only option to customize is through extensions.