Beverage wholesaler jumped six Odoo versions – 12 to 18 – in ten weeks

The starting point

Roughly 60 staff, 35 Odoo users, thousands of order lines a week across two warehouses. Odoo 12 Community, implemented in 2019, had grown 41 custom modules – routing rules, label printing, price-list logic – all by a freelancer no longer available. No upgrade since go-live: the version was out of security support, the barcode app was ancient, and every new feature request meant touching unmaintained code nobody understood.

What we did

• Weeks 1–3 – code audit. All 41 modules classified: 17 obsolete (the feature is now standard in Odoo 18), 10 replaceable with maintained OCA modules, 14 genuinely custom and worth rewriting.
• Weeks 3–7 – staged migration. Database migrated 12 → 14 → 16 → 18 with OpenUpgrade on copies; seven years of stock moves archived to keep the working database fast; the 14 keeper modules rewritten for Odoo 18.
• Weeks 8–9 – warehouse rehearsal. Pickers and drivers ran a full test day on the new barcode app against a migrated copy; three label-printing bugs found and fixed.
• Week 10 – cutover weekend. Final delta migration Saturday, verification Sunday, live Monday 6:00.

The result

A security-supported system with a third of the custom code to maintain. The monthly invoice batch that used to occupy accounting for three days now runs in about four hours with Odoo 18's automation. Future upgrades are a planned, priced exercise instead of a feared one – the next jump (18 → 19) is scoped at a fraction of this project.

"Ten weeks sounded too fast for six versions. The Monday after cutover, the warehouse simply started scanning – that was the whole drama."

Head of logistics, beverage wholesaler (name withheld – reference available on request)