What if the customer is not paying Maintenance for a PSUS development?
If customer is not paying maintenance fee ($5/Hour) or LOC MRR, then it’s not covered under Maintenance, hence we can not provide the custom code upgrade service.
Request custom code upgrade at the same time of requesting test upgrade.
If target version has some feature dropped/removed and If technical team used those feature in development then developers will try their best to make it compatible to the target version.
It may require success pack hours in order to re-engineer the initially developed solution.
Code upgrade will be done with target standard odoo version before it can be tested with upgraded database.