Perhaps devise a mapping file of the entire range of possibilities in the form:

this_version_tablename1.col1|version-1_table_col|version-2...

this_version_tablename1.col2|...

...

this_version_tablename2.col1|...

...

...

Leaving blank the places where the column did not exist in the relevant version. i.e. the columns delimited by '|' represent database versions and each such column could be in the form version.table.column

Then given any source version, all the data can be migrated automatically to any target version according to the table with the help of a simple script that:

- reads the mapping file into a AoHoH (array of version of hash of table of hash of column)

- uses that to iterate reading in from any old version database and to lookup where in the new database to put it.