Odoo 20 launched earlier this year, and with the upgrade tools expected to go live at the end of November 2026, every UK business currently running an earlier version is facing the same question: when do we upgrade, and is it worth doing at all?
It’s not a straightforward answer. Some businesses should move immediately. Others would be better served waiting 6 to 12 months. A small minority would get more value from standing still while they plan a bigger strategic change. This guide is a framework for working out which category your business sits in.
What’s actually different in Odoo 20
Before the framework, the context. Odoo 20 isn’t a cosmetic release. The changes that most affect UK buyers are:
☑️ A new Light User licence tier for operational staff who only use Planning, Shop Floor or Payslips, with material cost impact for manufacturers and multi-site operations
☑️ A reworked AI functionality that routes through Odoo’s own credits system rather than the previous Bring Your Own Key setup for OpenAI or Anthropic
☑️ A 25% legacy surcharge on contracts for Odoo 16 and earlier that haven’t upgraded. The commercial pressure to move is deliberate
☑️ Field Service has been consolidated into the Planning app, with 7 new features for teams running on-site operations
☑️ Accounting improvements including bill line prediction, auto-reconciliation and bulk reset-to-draft actions
☑️ Manufacturing gains including vendor quality rate tracking and the stock aging report
The upgrade itself is well-handled by Odoo’s tools for standard setups. Customised environments need a proper technical review before and after.
The 5 factors that decide your timing
When we walk UK clients through the upgrade question, these are the 5 factors that matter most.
Factor 1: What version are you currently on?
If you’re on Odoo 19, the upgrade to 20 is a standard annual move with no particular urgency. Plan it for the next natural project pause in your business calendar.
If you’re on Odoo 17 or 18, you’re not yet in surcharge territory but you’re one or two releases behind. Upgrading in the next 6 months keeps you close to the current version without immediate commercial pressure.
If you’re on Odoo 16 or earlier, the 25% legacy surcharge is already affecting your contract. The commercial case for upgrading is strongest for this group, and continuing to delay generally costs more than moving.
Factor 2: How customised is your current environment?
A near-standard Odoo environment with minimal custom code upgrades in a relatively straightforward way. The main work is testing rather than rebuilding.
A heavily customised environment with multiple custom modules, bespoke Studio changes, and third-party integrations requires a proper pre-upgrade review and a longer project timeline. If this describes your setup, don’t rush the upgrade. Plan it properly over 2 to 3 months to avoid go-live problems.
Factor 3: What’s your business calendar look like?
Odoo upgrades are projects that consume internal time as well as partner time. The worst time to upgrade is the month before your financial year-end, your annual peak trading period, or a major contract renewal that requires finance team focus.
The best time is 2 to 3 months after a quieter season, when your team has capacity to test, train and adapt to the new version.
Factor 4: Will you use any of the new functionality?
The Light User tier is the single biggest reason to upgrade sooner rather than later for any business with a large operational team. For a 30-person manufacturer, the licence cost difference can be material month-to-month, and that saving usually pays for the upgrade project itself inside 12 to 18 months.
The AI functionality changes are worth considering carefully if your current environment uses OpenAI or Anthropic through BYOK integrations. Depending on how those workflows are structured, moving to Odoo’s credits system could cost you more or less than your current setup. Worth modelling before you move.
The Field Service and Planning consolidation is a straightforward improvement for anyone running on-site operations.
Factor 5: Is there a bigger strategic change on the horizon?
If you’re planning a significant business change in the next 6 to 12 months, for example a merger, a major new site, a shift in your product or service mix, or a new finance system, it’s worth considering whether to time the Odoo upgrade to coincide with that change rather than running two disruptive projects in parallel.
This is the most common reason we recommend clients wait. It’s not that the upgrade is a bad idea, it’s that doing two major operational projects simultaneously almost always lands both of them badly.
Who should upgrade now
Businesses on Odoo 16 or earlier where the legacy surcharge has become uncomfortable.
Businesses with large operational teams who will benefit materially from the Light User tier.
Businesses running Field Service who can take advantage of the new consolidated Planning module.
Businesses with a clear 2 to 3 month window of operational calm in their business calendar.
Who should wait 6 to 12 months
Businesses on Odoo 17, 18 or 19 with heavy customisation that needs proper review.
Businesses planning a major unrelated operational change in the near term.
Businesses whose finance team is already stretched by other projects.
Who should consider not upgrading at all
A small group, but worth naming. If your business is actively evaluating whether Odoo is still the right platform for you, or if you’re planning a strategic exit where the new owner will make their own ERP decision within 18 months, there’s a case for staying put until that decision is made.
Equally, a business that’s barely using Odoo and would get more value from a simpler system might find the upgrade is an opportunity to reconsider the whole setup, rather than to invest further in the current one.
What to do next
If you’re weighing up the upgrade and want a second pair of eyes on which timing category fits your business, we’d be happy to walk through your situation. Drop us a message or book a 20-minute call via our contact page. Whether you’re currently working with another partner, running Odoo in-house, or just starting to think about the question, we’ll give you a straight read on what makes sense for your specific setup.