Odoo · ERP · Peru
Odoo 19 vs Odoo 18: what changes for a business
For a company already running Odoo 18, the upgrade question is not what is new. It is what your custom developments will cost in the new version.
Last updated: September 2026
Score by criterion
Result by option
What actually determines the effort
Not the release notes. Three things: how many custom or third-party modules you run, how much they touch core behaviour, and whether anyone still uses what they do. A clean standard installation upgrades comparatively easily. An installation with five years of accumulated custom work is a project.
The pre-upgrade review
Before committing to a date, inventory every non-standard module and sort it into three groups: replaceable by standard functionality, must be rewritten, and should be dropped because nobody uses it. That third group is usually larger than expected, and every module you drop is maintenance removed permanently.
What to test, and with what
Your own processes, on a copy of your own data, down to the journal entry. Release notes tell you what changed in the product; only your data tells you what changed for you. Pay particular attention to anything touching taxes, document numbering and inventory valuation.
Localization
Peruvian localization behaviour can change between versions, and so can the interface with your electronic invoicing provider. Confirm compatibility with that provider explicitly before scheduling the upgrade, not during it.
When to upgrade, and when to wait
Upgrade when a version brings functionality you will actually use, when your custom footprint is small, or when your current version is approaching the end of its support window. Wait when you are mid-implementation, mid-close, or when nobody has reviewed the custom modules yet.
Feature lists, support windows and localization details are published by Odoo and updated over time. Confirm the current details for both versions before planning, rather than relying on a summary.
Frequently asked questions
Is upgrading every year necessary?
No, but versions are supported for a limited period. Skipping several in a row makes the eventual upgrade larger than the sum of the ones you avoided.
How long does an upgrade take?
Days for a standard installation; weeks when custom modules have to be reviewed and rewritten. The review, not the upgrade itself, is where the time goes.
Will we lose customisations?
Not if they are reviewed and migrated deliberately. What breaks quietly is custom work nobody documented and nobody remembers requesting.