Metadata fixes are updates to the source code of Operations. For over-layering we would use the These are used to code-merge over-layered code, but they are still needed on extension projects as this is part of the process to push updates downstream to the build, test, and eventually, the production environment.

The process of applying the updates is straightforward; it is the process that is the most important aspect to take away from this.

LCS can see which metadata fixes are available for each environment connected to the project. When working on a customer implementation project, use the Sandbox (test) environment as the reference VM to check for updates. When working on internal or ISV projects, use a reference VM hosted in Azure for this. On-premise implementations will be connected to LCS and will be handled in the same way as Azure-based implementation projects.

The cycle is as follows:

• Check the availability of metadata fixes required against a reference VM or environment
• Download the desired fixes to a development VM
• Apply the hotfixes so that they are placed in TFS
• Check-in so that a build is triggered (and other developers can bring down the hotfixes applied, maintaining the same code base across developers)
• Deploy the resultant package to the test environment (or reference VM)

When moving to the latest update release, where new VMs are deployed with the new update, we remove the hotfixes from source control before connecting the new dev VMs back to the source control project with the upgraded code. This process may change, and the standard documentation covers this very well. The process is described in the following link:

Overview of moving to the latest update of Dynamics 365 for Operations (https://docs.microsoft.com/en-us/dynamics365/operations/dev-itpro/migration-upgrade/upgrade-latest-update)