Start OpenMRS platform on Core 2.1.1 (using OpenMRS SDK for instance).
Let the Core Liquibase migrations run.
Once migrations are done and server fully started, stop the server.
Add the Bahmni 0.91 modules to the installation: bacteriology, operating theater and bahmni core.
Start the server again.
Confirm that Liquibase migrations are failing and Bahmni Core module won't start.