import the origin database to migrate on local computer
Uninstall all useless Odoo add-ons. Warning: do not uninstall add-ons for which the disappearance in the finale version is managed by Open Upgrade scrips.
Unsure all the add-ons are migrated in the final Odoo version
(optional) De-active all the website views

Local Migration process

launch the origin database ORIGIN_DATABASE_NAME with original version of Odoo, with odoo service ORIGIN_SERVICE
launch the following command:

./upgrade.sh {ORIGIN_VERSION} {DESTINATION_VERSION} {ORIGIN_DATABASE_NAME} {ORIGIN_SERVICE}

ex: ./upgrade.sh 14 16 elabore_20241208 odoo14

Deploy migrated base

Retrieve the migrated database (vps odoo dump)
Copy the database on the concerned VPS
vps odoo restore

Manage the add-ons to uninstall

The migration script will manage the uninstall of Odoo add-ons:

add-ons we want to uninstall, whatever the reasons
add-ons to uninstall because they do not exist in the final Odoo docker image

At the beginning of the process, the script compare the list of add-ons installed in the origin database, and the list of add-ons available in the finlal Odoo docker image.

The whole list of add-ons to uninstall is displayed, and needs a confirmation before starting the migration.

Manage migration issues

As the migration process is performed on a copy of the orginal database, the process can be restarted without limits.

Some Odoo migration errors won't stop the migration process, then be attentive to the errors in the logs.