Custom API is a great feature added to Dataverse. It gives you many flexibilities and can create complex JSON requests or response messages. In order to learn how you can make complex JSON messages; check out this post.

Now the issue at hand is we created a Custom API in our Dev instance and associated a plugin to it. Since then we had deployed the components to higher environments as a managed solution.

Later, we identified that we do not need this Custom API and we want to delete it. So we did the following which did not work:

• Delete the Custom API and its associated request & response parameters
• Unregister the Plugin using Plugin Registration Tool
• Remove the plugin code from the code assembly
• Updated the new assembly using Plugin Registration Tool

After doing all of the above steps in Dev we initiated the deployment to the higher environment using a regular update solution method. This failed with the following error:

Existing plug-in types have been removed. Please update major or minor verion of plug-in assembly.

I tried several things to see if I can fix the higher environment itself but I ran into managed solution issues. But when we did the following steps that worked for us:

• Remove the Custom API and its associated request/response parameters from Dev
• Deploy the managed solution to the higher environment using the stage & upgrade method so that the Custom API components are deleted
• Manually unregister the plugin using Plugin Registration Tool in Dev
• Remove the plugin code from the code assembly
• Updated the new assembly using Plugin Registration Tool in Dev
• Manually remove the plugin from all the higher environments
• Deploy the managed solution to the higher environment using the update method