Odoo’s upgrade tools for version 20 are expected to go live at the end of November 2026. If your business is planning the move, this is the window to start getting your current environment ready, rather than discovering the surprises at go-live.
The upgrade itself is well-handled by Odoo’s tools. The parts that cause late-stage issues are almost always the customisations, integrations and data edges that were made for your specific business over the years. These are the 5 technical areas worth checking before your implementation partner runs the upgrade.
1. Studio-built customisations
Studio is one of Odoo’s most useful tools, and it’s also one of the most common sources of upgrade friction. The upgrade tool handles standard Studio changes well, but complex Studio customisations sometimes behave differently in a newer version, particularly where multiple Studio modifications interact with one another.
Worth reviewing:
☑️ List every Studio customisation currently active in your environment
☑️ For each one, note what it does and who uses it
☑️ Flag any that touch finance, inventory or payroll flows as high priority
☑️ Have your implementation partner test the more complex ones in a staging environment before go-live
If anyone outside your usual implementation partner has built a Studio customisation in the past, make sure it’s in the review list. Those are the ones that tend to get forgotten.
2. Custom modules
Custom modules that touch record rules, tracking values or inherited views are the second major source of upgrade issues. Odoo 20 changes some underlying behaviour in these areas, which means custom code written against older versions may need refreshing.
On your checklist:
☑️ Pull a list of all custom modules installed in your environment
☑️ Identify any that override standard Odoo behaviour in record access, security rules, or form inheritance
☑️ Any custom module older than 18 months without a recent review is worth a specific check
☑️ Budget time with your development partner to test each one in a staging environment running Odoo 20
Custom modules that haven’t been touched for a while tend to be the ones that quietly break. Not because of anything dramatic, usually because standard Odoo has moved on and the custom code is still assuming an older behaviour.
3. Field Service (now inside Planning)
The Field Service app has been consolidated into Planning in Odoo 20. For most users this is a positive change because it means scheduling, dispatching and field work all sit in one view. For anyone who’s built custom reports, integrations or workflows pointing to the old Field Service model, there’s rework to do.
What to check:
☑️ List all reports or dashboards that reference Field Service records
☑️ List all integrations (CRMs, scheduling tools, customer portals) that send or receive Field Service data
☑️ Any Zapier, Make or custom API integration tied to the old Field Service model needs reconnecting to the new Planning structure
☑️ The 7 new Field Service features in Odoo 20 (live technician map, customer equipment tracking, travel fees, website form, customer ratings, product barcodes, customer history) are worth evaluating as part of the upgrade, not as a separate project afterwards
4. Employee records in HR
Odoo 20’s new Light User tier (£7 per user per month in the UK) counts employees used in Planning, Shop Floor or Payslips. This makes the upgrade a good practical moment to tidy up any dormant employee records that have been sitting in your system longer than they should.
Worth reviewing:
☑️ Go through the full employee list in HR
☑️ Archive leavers whose records have never been closed
☑️ Check for duplicate employee records (common where someone’s been rehired or where a contractor has multiple profiles)
☑️ Confirm which employees genuinely need Light User access versus full user access, so your licence allocation reflects actual usage after the upgrade
Tidying this before the upgrade means your Light User count is accurate from day one, which affects your monthly licence bill under the new pricing model.
5. AI integrations
If your current Odoo environment uses AI features through your own OpenAI or Anthropic API keys (a Bring Your Own Key setup), the upgrade to Odoo 20 is a significant change. Odoo 20 routes all AI functionality through Odoo’s own credits system rather than external keys.
On your checklist:
☑️ List any current AI integrations that depend on your own API keys
☑️ Map what each one does and how often it runs
☑️ Work with your partner to understand how Odoo’s credits system will meter equivalent usage
☑️ Budget for Odoo credits in your post-upgrade operating costs
Some workflows will run cheaper under Odoo credits, others will run more expensively. Running the numbers before the upgrade gives you a cleaner view of the operating cost change, rather than discovering it on your next invoice.
When to start
If you’re planning to upgrade in the first quarter of 2027, now is the right moment to begin working through this checklist. The full review typically takes 2 to 4 weeks depending on how complex your environment is, and the remediation work to fix anything that surfaces usually takes another 4 to 6 weeks. That timeline puts a January or February go-live well within reach.
The alternative, which is leaving the review until the week before the upgrade, usually ends with either a delayed go-live or a weekend of firefighting none of your team signed up for.
Planning your Odoo 20 upgrade?
If you’re planning your move to Odoo 20 and want a straight read on how ready your current environment is, drop us a message. We work with businesses across all Odoo versions, whether you’re currently supported by another partner, running Odoo in-house, or still deciding whether the upgrade is worth doing at all.
If you’re on Odoo 16 or earlier and the 25% legacy surcharge is pushing you to decide this year, that’s exactly the kind of conversation we can help with. Book a 20-minute call via our contact page and we’ll walk you through what to check in your specific situation.