Will Excel workbooks work in Collabora Online for our teams?
XLSX is a supported format in Collabora Online, but whether a given workbook behaves the same way depends on the features it uses. Finance and operations teams moving from Excel desktop or another hosted office suite to Collabora Online inside Nextcloud or another WOPI host should not treat format support as a yes or no answer. A workbook with simple ranges and totals will usually open and recalculate without trouble. A workbook built on dynamic arrays, pivot tables, macros or heavily formatted charts needs a specific check before anyone relies on it for month-end close or operational reporting.
This page covers how Collabora Online handles the Excel features that most often change in transit: formulas including dynamic arrays and XLOOKUP, pivot tables, charts, conditional formatting and macros. It also describes how to choose which workbooks to test first and what to record when a result differs from the desktop original. Collabora Online is built on LibreOffice technology, according to the Collabora Online product page, and it reaches your document store through the WOPI protocol, so the spreadsheet engine and the host application each play a part in what users see.
Before committing to a rollout date, ask the vendor and your own team to confirm the exact Collabora Online release line you will run and its support status for the formulas and objects your critical workbooks contain. Do not infer support for a function from the fact that the file opens. Plan to round-trip a representative set of workbooks through Collabora Online and back to Excel, and treat any change to a calculated result as a blocking issue until someone who owns the workbook has signed it off.
Which spreadsheet features need the closest review
Excel workbooks rarely fail as a whole. They fail in a few specific features whose behavior depends on the calculation engine, the file format writer and the macro runtime. The cards below group those areas so you can test each one against the Collabora Online release you run, using your own critical workbooks rather than a generic sample.
Dynamic arrays and XLOOKUP
Dynamic array formulas spill results into neighboring cells, and XLOOKUP and similar newer functions depend on how the engine evaluates arrays and handles missing matches. Check that each spilling formula returns the same range, that the spill boundary survives a save and reopen in Excel, and that lookups with exact match, wildcard and not-found arguments return the values your model expects. Confirm the function list and array behavior in the release you run before assuming parity.
Pivot tables
Pivot tables are stored as cache definitions plus a layout, and a round trip can change field order, grouping, calculated fields or refresh behavior. Open each pivot, change a filter, refresh the source range and save back to XLSX, then reopen the file in Excel. Look for lost slicers, altered number formats and pivots that refresh to different totals. Treat any pivot that feeds a report as a blocking test case until it passes.
Charts and chart formatting
Charts store series references, axis settings, data labels and styling in separate parts of the file, and a change in one renderer can shift a label, a legend or a trendline. Compare each critical chart before and after a round trip, including combo charts, secondary axes and linked titles. Visual differences are common and often cosmetic, but a series pointing at the wrong range is a data error and should be logged as a blocker.
Conditional formatting
Conditional rules that use formulas, color scales, data bars and icon sets are interpreted at render time, so a rule that looks correct in Excel may highlight different cells after a save. Test rules with relative references, overlapping ranges and stop-if-true priority. Confirm that thresholds driving red-amber-green status in management reports still trigger on the same values after the file has been edited in the browser.
Macros and VBA projects
Office macros are a security surface as well as a compatibility question. Determine whether your workbooks contain VBA projects at all, since Collabora Online does not run VBA the way desktop Excel does, and decide whether macro-enabled workbooks are opened, blocked or converted in your deployment. Confirm the behavior of any macro-free equivalent, and document the decision with your security team, because it affects both users and the hosting policy.
External data and links
Workbooks that query external sources, link to other files, or use data connections depend on credentials, network paths and file locations that differ in a self-hosted WOPI setup. Inventory every external link and connection in your critical files, then verify whether links update, prompt, or fail when the file is opened from Nextcloud or another host. Also confirm how the host restricts outbound requests, since a blocked link can silently break a model that depends on it.
How XLSX files are opened, saved and round-tripped
Collabora Online opens and saves XLSX files through its LibreOffice-based calculation and file filter engine, not through Microsoft Excel. The practical consequence is that a workbook can look correct on screen in the browser and still change when it is saved. Formula results, cell formatting, number formats, column widths, data validation and object positioning are all rebuilt from an internal model during save, so any feature that the internal model represents differently from Excel can come back altered. Treat the first save of any business-critical workbook as a transformation, not a copy, and plan a comparison step before users rely on the output.
The round-trip risk is the case that matters most for rollout: a file is opened and saved in Collabora Online, then reopened in Excel by a colleague, auditor or external partner. Check the reopened file for the items that carry logic or meaning, including formulas that depend on dynamic array behavior, lookup functions, external links, named ranges, pivot table refresh behavior, chart series references and conditional formatting rules. Run this check on a copy of each workbook, record the differences in a simple register, and decide which differences are cosmetic and which block go-live. The test corpus approach described in the sibling testing topic is the right place to store these results.
The supported format list for Collabora Online includes xlsx, but a listed format is not a guarantee of fidelity for every workbook feature. Read the release notes for each branch you plan to run, for example the Collabora Online release notes, and look for spreadsheet fixes between branches such as 25.04 and 26.04 that touch the features your workbooks use. Confirm with Collabora which fixes are in the exact build you will deploy, and retest critical workbooks after every point release, since a fix in one branch may still be absent from the branch you run.
Configuration choices that affect spreadsheet editing
This table compares the settings and purchasing choices that change how XLSX workbooks behave in Collabora Online. Read each row for when the option fits and what it costs you in fidelity control, support or risk. The main takeaway is that format, editor permissions, edition and version pinning should be decided before a critical workbook is tested, not after users report problems.
| Decision | Option | Trade-off | When it fits |
|---|---|---|---|
| Default save format | Save new workbooks as OOXML (xlsx) in the WOPI host | Keeps Excel-native structure for Excel users, but formula and chart behavior still needs testing per workbook | Workbooks exchanged with Microsoft Excel users or external partners |
| Default save format | Save new workbooks as ODF (ods) in the WOPI host | Clean open standard, but Excel users may see differences in advanced features after round trips | Organizations with an ODF policy or where workbooks stay internal |
| Editor and edit groups | Limit the editor to specific groups in Nextcloud Office | Narrows who can open spreadsheets in the browser, which adds administration work as teams change | Finance or reporting teams with critical models |
| Editor and edit groups | Allow view-only access for other groups | Prevents accidental formula edits, but users who need changes must be added to the edit group | Read-heavy audiences such as management or auditors |
| Edition | Free CODE image for testing or small teams | No supported plan; Collabora does not recommend CODE for production, so spreadsheet fixes arrive on its own release schedule | Pilots and fidelity testing before a purchase decision |
| Edition | Business plan at 3 euros per user per month for up to 99 users | Recurring per-user cost, with long term support, SLA and signed security updates included, per Collabora's pricing page | Production use by a defined user population under 100 |
| Edition | Enterprise plan for 100 or more users | Quoted with volume discounts and includes integration support, customization services and roadmap input | Large deployments needing custom work or direct vendor input |
| Branch version | Pin a long term supported branch such as 25.04 for stability | Fixes from newer branches must be backported or upgraded deliberately, and upgrades must be retested against your workbooks | Environments where workbook regression testing is scheduled and controlled |
Testing critical spreadsheets before rollout
This sequence turns a general fidelity concern into a short, owned list of workbooks that either pass staging checks or block go-live. It ends with a documented decision for each critical workbook, so the rollout team knows which files are safe to edit in the browser and which need a different path.
Inventory workbooks by owner and criticality
Ask each business unit to list the workbooks their teams open, edit or publish, and name a business owner for each one. Rank them by how much harm a wrong number or broken chart would cause, such as financial close, regulatory reporting, pricing or payroll. Check that every critical workbook has an owner who can confirm expected results. The output is a register with file name, owner, criticality, and the features each file uses.
Build a representative workbook corpus
From the register, select copies of real workbooks (with sensitive data removed or replaced) that cover the features your teams depend on: dynamic array formulas, XLOOKUP, pivot tables, charts, conditional formatting, data validation and any macros. Where a live file cannot be shared, build an illustrative test workbook that reproduces the feature and its formula chain. Check that each feature in the register appears in at least one test file and keep the original .xlsx unchanged as the reference copy.
Record baseline results in Excel
Before testing in Collabora Online, have the business owner open each reference workbook in desktop Excel and record the values that matter: key totals, lookup results, pivot summaries, chart series and the rules that drive conditional formatting. Save the expected values in a simple sheet alongside the file name and the Excel version used. The check is complete when every critical workbook has a documented set of expected results signed off by its owner.
Test in staging behind production WOPI settings
Deploy a staging Collabora Online server and point a non-production Nextcloud or other WOPI host at it, using the same allow list, protocol, TLS and access settings you plan to use in production. Open each corpus file, make representative edits, save, reopen and close. Check that the file loads from the WOPI host, saves back without errors, and that the staging configuration matches the production one line by line. Record any login, permission or proxy problem separately, because it is not a spreadsheet fidelity issue.
Compare results against the Excel baseline
Download each edited file from the staging host and open it in desktop Excel. Compare the recorded values, formula results, pivot refresh behavior, chart appearance and conditional formatting against the baseline. Also check the reverse direction by opening a file saved in Excel in Collabora Online and confirming that it recalculates to the same results. Compare the results line by line. The output is a comparison sheet per workbook marking each check as matched, changed or not supported.
Log issues and assign severity
Record every difference in an issue log with the file name, feature, steps to reproduce, the Excel result, the Collabora result and a severity. Classify differences that change a number or break a dependent calculation as high, differences in appearance or formatting as medium, and cosmetic differences as low. Have the business owner confirm the severity for their workbooks. The check is that every mismatch has an entry, an owner and a severity before the review meeting.
Decide go-live blockers and workarounds
Review the issue log with the business owners, security and the rollout lead. Mark any high severity issue on a critical workbook as a go-live blocker, and decide for each blocker whether to fix it, keep that workbook in Excel for now, or change the workbook design. Confirm the vendor's current position on any unsupported feature with Collabora or in your own environment before relying on it. The output is a signed decision record that names the workbooks cleared for browser editing and the ones that are not.
Repeat tests after each Collabora update
Keep the corpus, baseline and comparison sheet under version control, and rerun the sequence before each Collabora Online upgrade and after changes to the WOPI host configuration. Compare the new results with the previous run and log any regression as a new issue. The check is that each upgrade has a recorded test run and a decision on any new blockers before it reaches production. For the fidelity test method itself, see the sibling page on testing document fidelity before a Collabora Online rollout.
Macros, external links and access controls for workbooks
Workbooks carry more security exposure than their file size suggests: macros, external links and the server path that delivers them can all reach systems you did not intend. The cards below cover the decisions to make before rollout and the controls that enforce them in a Nextcloud and Collabora Online setup.
Macro handling policy
Decide whether macro-enabled workbooks may be opened, edited or saved in Collabora Online at all, and write that decision down before pilot users start. Test how your current Excel macros behave in the browser editor, because VBA-dependent logic may not run or may run differently. Confirm the exact macro behavior for your version with Collabora before relying on it, and plan a separate path for workbooks that must keep macros, such as keeping them in Excel on managed desktops.
External data links and connections
Workbooks can contain links to other files, to databases and to web sources. Check which of your critical spreadsheets contain external references, and decide whether the browser editor should refresh or follow them. A link that resolves to an internal file share or internal API can expose data to the editing session, so review target addresses before rollout and confirm with Collabora how link updates are handled.
Restrict WOPI requests to Collabora servers
The Nextcloud administration manual recommends restricting WOPI requests to the IP addresses of the Collabora servers, so that only your Collabora instance can call the WOPI endpoints. Pair this with the same protocol for the Collabora server URL as for Nextcloud, preferably HTTPS. Verify the allow list after every change to load balancers or proxies, because a wrong source address will break editing rather than fail quietly.
Group-based edit rights
In Nextcloud Office, administrators can limit which groups can use the editor and which groups can edit rather than only view. Use this to keep finance or reporting workbooks read-only for most staff and editable only for named owners. Test both roles with a copy of a critical file, since a view-only user who can still save or export changes would undermine the policy.
Patching from Collabora advisories
Collabora publishes security advisories for Collabora Online. The 25.04 release notes record that 25.04.7.5, released January 29, 2026, fixed CVE-2026-23623 and that package signing keys were updated for RPM and DEB users. Subscribe to advisories for your branch, schedule point releases, and re-run your workbook test set after each update so fixes do not change spreadsheet behavior unnoticed.
What to confirm about spreadsheet limits in your environment
Which dynamic array and XLOOKUP results will Collabora Online calculate in our release?
Collabora Online uses LibreOffice calculation, so the answer depends on the exact release branch you deploy, and you should confirm function support for that branch with Collabora before you commit. Ask for the list of Excel 365 functions, including dynamic array spill behavior and XLOOKUP with its match modes, that the release calculates correctly. Then test it in your files: build a representative set of formulas that use spilled ranges, nested lookups and error handling, open them in Collabora Online, and compare every computed cell against the values saved by Excel. Record any cell that shows a different value, a #NAME? error or a stale result after recalculation.
How reliably do pivot tables refresh and stay editable in Collabora Online?
Pivot table behavior is a common gap between spreadsheet suites, so treat it as something to verify rather than assume. Ask Collabora which pivot features are supported for editing, refreshing and changing layout in your target release, and whether source ranges and field settings survive a save back to XLSX. In your own testing, open each pivot, change a filter, add a field, refresh from the source data, and save. Then reopen the file in Excel and check that the layout, grouping and totals match. Keep a copy of the original so you can compare the pivot cache and the displayed values.
Do charts in Collabora Online look the same as charts saved from Excel?
Chart rendering can differ in fonts, spacing, axis labels, legends, number formats and some chart types, even when the data is correct. Ask Collabora which chart types and formatting options it renders faithfully from XLSX, and how it handles charts created in Excel that it does not fully support. Test by sampling every chart type your organization uses, including combination charts and charts linked to named ranges. Compare the rendered output with Excel side by side, and decide in advance which differences are acceptable for internal review and which block a document that goes to a client or regulator.
Which conditional formatting rules survive an edit and save in Collabora Online?
Conditional formatting depends on rule type, formula syntax and the priority order of overlapping rules, so confirm these with Collabora rather than relying on general statements about LibreOffice. Ask which rule types (cell value, formula-based, color scales, data bars and icon sets) are imported, edited and written back to XLSX without change in your target release. In your tests, build a sheet with each rule type your team uses, overlapping rules and rules that reference other sheets. Edit the source values, save, reopen in Excel and check that the highlighted cells and rule priorities still match.
Does Collabora Online run VBA macros from our workbooks, and what happens to them on save?
Collabora Online does not run Visual Basic for Applications macros from Excel workbooks in the way Excel does, and you should confirm the exact behavior for your release and for .xlsm files with Collabora. Ask what happens to macro-enabled files on open, whether the macro code is preserved on save, and whether any macros are executed at all. Test with a copy of each macro-enabled workbook, check that the file is not altered unexpectedly, and document which workflows must stay in Excel. Macro handling also belongs in your security review, so align the answer with your policy for macros in documents.
How does performance hold up on large workbooks with many formulas and sheets?
Load time, recalculation speed and memory use depend on workbook size, formula count, volatile functions, external links and the resources given to the Collabora Online server, so ask Collabora for their guidance on large spreadsheets for your release and for the sizing recommendations that apply to your concurrency. Test your largest real workbooks, not samples: time the open, a full recalculation, a bulk edit and a save, with several users editing different documents at once. The Helm chart README lists production resource requests and limits per pod, which is a starting point for the load test. Record where response times stop being acceptable and feed that into your sizing plan.
When to keep critical workbooks in XLSX or Excel
Keep the original XLSX as the system of record for any workbook that depends on features your Collabora Online tests cannot confirm. The decision is made per workbook, not per platform. Start with an inventory of the critical spreadsheets your teams rely on for finance, reporting, payroll, regulatory returns or operational planning, then mark each one that uses dynamic arrays, XLOOKUP-heavy models, pivot tables with slicers, complex chart types, macros or external data connections. Those workbooks stay in Microsoft Excel or in a controlled XLSX store, and Collabora is used for collaborative editing only where the round-trip tests in your own corpus pass. Confirm the exact behavior of each feature in the Collabora version you plan to run, because support changes between releases and the release notes are the authoritative record.
Communicate exceptions in writing before rollout, not after a user discovers a broken model. Give each exception an owner, a short reason, the approved way to edit it and a named fallback, such as opening the file in Excel through the desktop client or a managed Microsoft 365 tenant. Put the list in the same place users already look for guidance, and tell them which warnings or missing elements mean they should stop and switch. Where a workbook must be shared with external partners who work only in Excel, state whether the Collabora copy is a convenience view or an editable master, because two editable copies of one model is the most common source of silent divergence.
Re-test after every Collabora upgrade, including point releases, and treat the results as a gate for the workbooks marked as allowed. Keep the test corpus, the expected outputs and the checksum or recalculated values for each critical sheet, and rerun the same steps against the new build in a staging environment that mirrors your WOPI host configuration. Assign a reviewer who compares calculated values, formatting, chart rendering and macro behavior, and record any change in a dated log. If a regression appears, roll back the Collabora version or move the affected workbook back to the exception list until the fix is confirmed. Plan this re-test into your upgrade calendar from the start, since it is recurring effort that scales with the size of your corpus.
How DeployOpen scopes and delivers XLSX compatibility testing
DeployOpen plans, implements, tests and hands over Collabora Online deployments inside the client's own infrastructure, including the spreadsheet fidelity checks that sit between a workbook corpus and a go-live decision. Engagements are fixed-scope, so the workbooks, Excel versions, features and acceptance criteria are agreed in writing before any testing starts.
How we scope
- We inventory the workbooks you need to open, edit and save, grouped by business owner and risk.
- The written scope names the Excel features under test, such as dynamic arrays, XLOOKUP, pivot tables, charts and macros.
- We agree which Collabora Online and Excel versions are in the test matrix and what pass criteria apply.
How we build
- We build a representative XLSX test corpus from your critical spreadsheets, with sanitized data where needed.
- We run round-trip tests in Collabora Online and Microsoft Excel, recording formula results, chart rendering and formatting differences.
- We log each defect with a reproduction file, a severity and a recommended decision: fix, workaround or accept.
How we hand over
- You receive the test corpus, the test scripts, the issue log and a written go or no-go summary for each workbook group.
- We document the deployment settings used during testing so your operators can reproduce results.
- Handover includes a retest plan for future Collabora Online upgrades, so spreadsheet behavior is checked again before rollout.
How we support
- Ongoing support, upgrades and continuous testing are available as retainers after handover.
- A retainer can re-run the corpus against new Collabora Online branches before you upgrade.
- Confirm with us during scoping which support level, response terms and service agreement you need for your environment.
