Upgrading keycloak from 12.0.2 to 15.1.1

Getting advice
1

Hi,

I am trying to upgrade my keycloak from v12.0.2 to v15.1.1 and using H2 database. I’ve managed to upgrade the server to v15.1.1 and started the application successfully, however once the service was restarted it wouldn’t work anymore.

Caused by: org.h2.jdbc.JdbcSQLException: Constraint "FK_5HG65LYBEVAVKQFKI3KPONH9V" already exists; SQL statement:
ALTER TABLE PUBLIC.REALM_REQUIRED_CREDENTIAL ADD CONSTRAINT PUBLIC.FK_5HG65LYBEVAVKQFKI3KPONH9V FOREIGN KEY(REALM_ID) INDEX PUBLIC.FK_5HG65LYBEVAVKQFKI3KPONH9V_INDEX_9 REFERENCES PUBLIC.REALM(ID) NOCHECK [90
045-197]

Same issue happens if try and migrate it to v13,v14 and v15.

Any advise is greately appreciated.

Thanks,