Database schema not updated properly

When running Manifold 1.6 the first time with an database schema from Manifold 1.3 the schema is not updated properly. The SQL-command

"ALTER TABLE authconnections MODIFY groupname VARCHAR(32) NOT NULL REFERENCES authgroups(groupname) ON DELETE RESTRICT"

fails. It should instead add the column:

"ALTER TABLE authconnections ADD groupname VARCHAR(32) NOT NULL REFERENCES authgroups(groupname) ON DELETE RESTRICT"

The next startup after executing the corrected SQL-statement succeeds.