Microsoft is hard sealing the Dynamics 365 for Finance and Operations application suite as of version 8.0 (the Spring 2018 release), so customizations will now be done using extensions rather than overlays. This will make upgrades and implementations faster and easier, and lower the cost of code ownership. (You can learn more about the benefits of extensions vs. overlays in our recent post.)

Microsoft has released this schedule for the transition:

• Pre-Spring 2018 release (8.0) focus – ISV solutions
  • 120+ of 170 AppSource applications are overlay free as of 8.0
• Post-Spring 2018 release (8.0) focus – Implementation projects and ISV solutions
  • Minimize implementations that must fall back to Fall 2017 release (7.3) due to overlaying
• Version 10.0 (Spring 2019) – all customers running on extension-only implementations
  • Exceptions for implementations that have outstanding extension requests with Microsoft

Creating Extensibility Requests

When transitioning code from overlays to extensions, you may come across objects that are not extensible. You then need to submit an extensibility request to Microsoft. Here's how to create a request quickly and easily in Lifecycle Services (LCS).

• Open your project in LCS.

• In the tool bar, select Support.

• Create a new extensibility support request.

• Documentation: https://learn.microsoft.com/en-us/dynamics365/fin-ops-core/dev-itpro/extensibility/extensibility-home-page