Liquibase update

When trying to upgrade liquibase on a database with an existing DATABASECHANGELOG table from liquibase version 1.9 to the new 2.0 version liquibase failed to insert the new changeset entries due to missing or to narrow columns.

I don't know why, but I did not find any instruction how to upgrade an existing changelog. So I diffed the former and current table definitions and extracted the following table modification:
ALTER TABLE DATABASECHANGELOG
ADD (ORDEREXECUTED INTEGER DEFAULT 0 NOT NULL)
ADD (EXECTYPE VARCHAR(10) DEFAULT 'EXECUTED' NOT NULL)
MODIFY (MD5SUM VARCHAR(35));

With the new changelog table liquibase 2.0 works on with the existing database.