It is cumbersome (and tacky) to re-trigger the updating code by changing the version in the configuration tree followed by a restart.
After migration of template scripts, some new areas can be found and these must be added to module configuration.
Previously, the only way to verify the result was putting the generated Delta tasks (MGNLMIGRATION-164) to VersionHandler of module and restarting the instance.

This is no longer the case though, because the configuration is updated right away and user
copies the Delta tasks only after he finds that migration was successful.

The process:

1. backup the snapshot of the old configuration and templates
2. trigger the migration
3. restore the original from backup or export migrated modules' bootstraps.