We recently upgraded from liquibase 1.9.5 to 2.0.3 and referred to the DB changes mentioned on the upgrade guide (http://www.liquibase.org/v2_upgrade).
As a background, we run liquibase in our development environments and for production/staging deployments use the scripts generated by liquibase (ant task updateDatabase) and run them manually.
We used the instructions in the upgrade guide to make changes to liquibase metadata tables in the DB and found the following issues:
a) It does have information about columns added to DATABASECHANGELOG - TAG, ORDEREXECUTED, and EXECTYPE. Not sure if TAG should be in the list of added columns. I do not know what version it was added, but we already had it in 1.9.5.
b) Also, it would be handy to have a list of modified columns…otherwise running the generated scripts manually on 1.9(.5) database does not work as the length of a couple of columns in DATABASECHANGELOG has been increased:
MD5SUM: 32 -> 35
LIQUBASE: 10 -> 20