Excellent news regarding the bulk updates; I just spent almost an hour in phpmyadmin moving data from version (which we'd been using as a 'target_version' version) to the new column. Hopefully this bulk update can also be applied to 'fixed_in_version', which people often forget to set (and then this messes up the changelog)
Why an hour, you say?
Well at the same time I renamed a couple of our versions, and this made my life harder because, well, I wasn't expecting the version columns to have the value directly in there, rather I was thinking it'd be a link to another table. Oops.
This also forced me to delete and re-create all our public queries, since, well, the version name changed, and they went to different columns.
I'll never rename the versions again. :)