Hello. I desperetly search for Help with OpenUpgrade and filestore managment.

I've got a dedicated instance of OpenUpgrade where I load the database I want to migrate. I use the migration.py script, latest version.

The problem: I got missing attachments after my migration. They are in the archive and I can found them on the server file system, but Odoo say they doesn't exists.

After checking the migrate.py script source code, it didn't modify
anything in the file store. So, the problem come from data about
attachment files that OpenUpgrade modify on the database. Or forget
to modify.

On my side, I wrote a shell script to automate a maximum the process.
This is what my script do:
- Unzip the Odoo database archive
- Extract the database name on the `manifest.json`
- Create locally a database with the name obtained from the manifest,
  the database is owned by odoo user.
- Restore the database file `dump.sql` in the database
- Restore the filestore on the right path and give it user odoo as owner
- Lunch `migrate.py` with the correct arguments (database, targeted version, etc)
- Copy the file store a directory with the `manifest.json`
- Modify the Odoo version in the `manifest.json`
- Dump the migrated database on a file named `dump.sql` and put it at side of
  the new version of `manifest.json` and the new filestore
- Build a zip archive with the `manifest.json`, the `dump.sql` and the filestore


At the end I obtain an archive I can restore on a version 9 of Odoo.
No error message during restoration. But, even with a filestore
restored, Odoo say it cannot find some attachments, like contact
photos, etc.

As I cannot find any info about the filestore and OpenUpgrade, or even
only on the filestore, I don't know if what I do is correct.