With the next release of Dynamics 365 for Finance and Operations Enterprise edition we plan to soft seal the Application Suite model.
For anyone not yet familiar with this agenda, please read through the previous announcement
The partner channel need to be educated for them to successfully migrate their development to using extensions instead of overlayering.
In order to help with that we have created a dedicated section on Extensibility in our documentation, which has a number of details about our plans, the process of migrating to extensions, as well as specific How to articles around platform capabilities, as well as specific application frameworks and how to extend them (coming soon...)
Home page for Extensibility documentation
If you cannot find a particular topic, let us know, either directly on the docs page, or here through comments to this post.
Hope this helps!