BizTalk 2020 with BTDF & Azure Pipelines - Application dependencies

Currently transitioning from BizTalk 2013r2 to 2020, and implementing Azure Pipelines to automate deployment with BTDF.

So far, we're able to deploy our Core applications, but we've just realised there are dependencies with the 'child applications' (applications that take schemas from the Core apps).

• How should I refer to the Core application within Visual Studio in our dev environment (we used to reference the .dll from the local repos solution)
• How can we configure BTDF and CI/CD pipelines to point to the correct application when deploying the child?
• What happens if we need to update the Core application via BTDF/Pipeline - we'll need to undeploy all child applications that reference it before we can deploy surely - can this be done via the BTDF config?

No, I don't believe that BTDF can take care of that.

You should either.

Version increase your assembly version number of your Core Application and do a side by side deployment (e.g. leave the original ones in place). Later on when you need the newer version in the dependent application then reference the later DLL (and yes, just have the DLL as an external assembly in the solution).

Or

Have your Core Application Pipeline undeploy all the dependent applications, before undeploying the Core Application and deploying it, and then re-deploying all the dependent applications.

My preference would be for the first option, less complicated.