code: protected ProcessDefinition findProcessDefinition(String processDefinitionKey, String tenantId) {
      if (tenantId == null || ProcessEngineConfiguration.NO_TENANT_ID.equals(tenantId)) {
        return Context.getProcessEngineConfiguration().getDeploymentManager().findDeployedLatestProcessDefinitionByKey(processDefinitionKey);
      } else {
        return Context.getProcessEngineConfiguration().getDeploymentManager().findDeployedLatestProcessDefinitionByKeyAndTenantId(processDefinitionKey, tenantId);
      }
    }
docs: Allow subclass to determine which version of a process to start.