Upgrading to Odoo 19 can bring real gains: faster performance, a cleaner interface, and deeper AI features across Sales, Accounting, and Inventory. But a migration that isn't planned properly can turn into days of firefighting instead of a smooth transition. Here's the checklist I walk clients through before any Odoo 19 upgrade. 1. Audit your current setup Before touching anything, get a full picture of what you're actually running. List every installed module, standard, third-party, and custom, and note which ones you actually still use. It's common to find modules that were installed once and forgotten. This is also the time to document your customizations and, importantly, why each one was made. That context matters later when deciding what's worth carrying forward. 2. Take a complete backup This step is non-negotiable. Create a full backup of your database and file store, and actually test that the restore works before you rely on it. A backup you've n...