Choosing the default document format in Collabora Online
The default document format is a policy decision driven by who receives the files. It is not a technical fix. Collabora Online supports OpenDocument formats and Microsoft formats such as docx, xlsx and pptx, so the editor can produce either family. The question is which format new documents take when a user creates them from a Nextcloud or other WOPI host session, and how much freedom users keep to choose another format when they save or export. Those behaviors depend on the WOPI host's office settings and the editor configuration, so confirm where each control sits in the versions you plan to deploy.
Make the decision before rollout, not after the first complaint from a partner. The format matters most when documents leave your organization. Partners, regulators and citizens may need files they can open without a Microsoft license, and some public sector bodies set ODF requirements in their own policies. Ask the organizations you exchange documents with which formats they accept, and record the answers. Templates and forms created under the default will carry that format forward, so review them at the same time. In Nextcloud Office, administrators can also limit which groups may use the editor and which groups may edit, which narrows the audience the default has to serve.
Before go-live, record the recipients and their format needs, then set the default in a test instance. Create a new document from each entry point your users will use, check the format it saves in, and test whether a user can change the format on save or export. Open the result in the partner's software to confirm it arrives intact. Keep the decision, its owner and the setting's location in your change record so that a later upgrade of Collabora Online or Nextcloud is checked against it. Confirm the exact setting name and its behavior in your deployed version against the Nextcloud Office configuration documentation.
Which factors push the default toward ODF or toward OOXML
If most of your external correspondence is with Microsoft Office users, OOXML (docx, xlsx and pptx) is usually the format recipients open without conversion. Saving new documents as ODF shifts conversion work onto partners, and that conversion can change layout, styles, comments and tracked changes. Choose the default based on where your files actually go.
- Recipient expectations: Ask your largest external senders and recipients which formats they send and accept, and whether they handle ODF attachments without friction.
- Round-trip loss: A document created as ODT and reopened in Microsoft Word can differ in pagination, fields and comments. Test your templates in both directions before changing anything.
- Corporate templates: Templates authored in Word are usually OOXML. A new default can split your template library into two sets that must be maintained in parallel.
- Spreadsheet and deck complexity: Workbooks with pivot tables, charts or macros and decks with custom masters need their own fidelity test, separate from text documents.
Before changing the default, check your top external partners' formats and run a round trip on your five most used templates in both Collabora Online and Microsoft Office.
Some public bodies have adopted policies that favor or require open formats for records or for exchange between agencies. Where a policy applies, the default becomes a compliance question, not only a usability preference. The wording decides the scope: a policy may cover archived records, published documents or only documents exchanged across organizations. The EU Interoperable Europe Act sets interoperability expectations for public sector services, and NIS2 names public administration as a sector of high criticality, but neither should be read as a format mandate without legal review.
- Policy scope: Establish whether the policy governs creation, storage, exchange or publication. A default change may satisfy one of these and miss the others.
- Accessibility obligations: For US state and local government, the ADA Title II rule requires web content to meet WCAG 2.1 Level A and AA from 26 April 2027 for entities serving 50,000 or more people, and from 26 April 2028 for smaller entities and special districts (28 CFR 35.200). Confirm which document formats your accessibility testing covers when files are published online.
- Records retention: Ask records managers whether long-term retention requires a specific format or a PDF archive copy. This is a separate decision from the editing default.
- Contract terms: Check whether grant terms, vendor contracts or procurement rules name the formats to be used.
Ask the owner of records or legal counsel for a written reading of each applicable policy, and map every obligation to the format it names.
Organizations that operate across countries, or whose partners sit under different rules, rarely have one uniform expectation. A single global default is simpler to support but can force conversions for some teams. The Nextcloud Office settings let administrators control which groups can use the editor and which can edit, so access segmentation is available, but confirm in your Nextcloud version whether format defaults can also vary by group before you design around it. Release timing matters too: the Nextcloud maintenance and release schedule sets which versions receive fixes, and Nextcloud 33 is supported until February 2027, Nextcloud 34 until June 2027 and Nextcloud 35 until September 2027.
- Global default versus exceptions: Document each exception with an owner, the partner group it serves and the review date, so exceptions do not drift into permanent conversion work.
- Version-specific behavior: Test format handling on the exact Nextcloud and Collabora Online versions you will run, because behavior can differ between releases.
- Data location: Keep the editing service inside infrastructure you control, so any conversion of sensitive documents stays within your environment and the jurisdictions you have approved.
- Partner software variance: Partners in different countries may use different office suites or versions. Test with the software your partners actually use, not with a generic Microsoft Office install.
Inventory the partner groups and jurisdictions that exchange files with you, and record the default and any exceptions for each group.
How the Nextcloud setting controls new document formats
The default format for new documents is set in Nextcloud, not in Collabora Online itself. Collabora Online renders and saves whatever the WOPI host asks it to edit, so the choice that decides whether a new Writer, Calc or Impress file starts life as OpenDocument or as a Microsoft format sits in the Nextcloud Office configuration. Before you change anything, confirm the exact configuration key, its default value and where it is stored in the Nextcloud version you run, since the administration manual is the authoritative reference for that version. The Nextcloud administration manual on Office configuration is the place to start, and it is also where you should check which groups may open and edit documents, because format defaults only matter for users who are allowed to create files in the first place.
On the Collabora side, the editor supports OpenDocument formats and Microsoft formats including docx, xlsx and pptx, plus PDF, RTF and CSV, so both defaults are technically workable. The practical constraint is not whether a format opens but how faithfully it round-trips. A file a user uploads as docx keeps its format when edited unless someone explicitly saves a copy in another format, so the default governs new documents and blank templates rather than existing files. Test this with your own templates: create a new document from each template type, edit it, save it, and confirm that the stored file extension and the format a recipient receives match what your policy requires. Record any differences in layout, tracked changes or spreadsheet formulas, because those will surface when the file leaves your environment.
Plan the default together with your external exchange rules, not as a cosmetic setting. If partners, regulators or public bodies require ODF, a Microsoft default will still produce docx files that must be converted before sending, and each conversion step is a point where fidelity can drift. If your users work mostly with Office recipients, an ODF default may add friction. Decide the default per document type where your policy allows it, write down who owns the setting and who approves a change, and retest after each Nextcloud or Collabora upgrade, because defaults and supported formats can change between releases.
Default format options and when each fits
This table compares the three ways to set the default save format in Collabora Online: OpenDocument, Microsoft formats, or a per-document choice. Read each row against your partner exchange obligations, any public sector ODF policy, and the fidelity risk when files return to Microsoft Office. The main takeaway is that the default matters less than the test results for the document types you actually exchange.
| Option | Partner exchange fit | Public sector ODF policy fit | Fidelity risk when files return to Microsoft Office | What must be tested before choosing |
|---|---|---|---|---|
| Default to OpenDocument (ODT, ODS, ODP) | Good when partners and archives accept ODF; weaker when counterparties open files only in Office | Strong fit where a written ODF requirement applies; confirm the policy wording | Higher for complex Word, Excel and PowerPoint files that round-trip through ODF before reaching Office users | Round-trip sample documents through ODF and Office; check tracked changes, styles and formulas |
| Default to Microsoft formats (DOCX, XLSX, PPTX) | Good when most external partners exchange Office files by default | May conflict with an ODF policy unless an exception is documented | Lower for Office users, since files stay in their native format; ODF-only features may be lost in other tools | Confirm the policy allows Microsoft formats; test the templates your teams reuse |
| Let users choose per document | Flexible, but partners receive mixed formats and need guidance | Can satisfy policy only if users are trained and new files are audited | Depends on each user's choice, so fidelity varies across the estate | Test both paths and decide how users are guided and how the choice is audited |
| Nextcloud setting that controls the default | Confirm in the Nextcloud Office settings which default format applies to new documents | Document the setting as part of the policy evidence | Verify after upgrades, since the setting's behavior should be confirmed in your release | Check the setting on a test instance before rollout and after each upgrade |
| Existing Microsoft-format document estate | Files already in DOCX, XLSX or PPTX may not need conversion for partners | Conversion of archives may be required by policy; scope it separately | Converting legacy files to ODF can change layout and formulas | Inventory file types and sample critical documents before deciding |
| Who decides and who signs off | Partner exchange owners confirm which formats they accept | Records, legal and accessibility leads confirm policy fit | Office support teams own user-facing fidelity issues | Record the decision, the test results and the exceptions in one document |
Setting the default format before rollout
This sequence moves the ODF or OOXML decision from an assumption to a documented, tested and communicated default. Each step ends with a check that the outcome is in place before the next step starts.
Inventory external file exchange paths
Before changing any setting, list every place documents leave your organization: partners, customers, regulators and public bodies that send or receive files. For each path, record the formats exchanged, who sends them, and whether the receiving system accepts OpenDocument files. Include email attachments, shared links and any integration that pulls files from Nextcloud. This list is the evidence behind the default decision. Done when each exchange path has a named owner and a recorded format, and each owner has confirmed the entry in writing.
Confirm the policy owner and decision
Name one accountable owner for the default format, usually someone with authority over records management or over any public sector ODF policy that applies to you. Ask the owner to record the chosen default, the exceptions for specific exchange paths, and who may approve exceptions later. Ask legal or procurement to confirm whether an ODF policy binds your organization. Done when the decision record is signed off and stored where administrators can find it during configuration.
Configure the staging environment
Build a staging Nextcloud and Collabora Online pair that matches production as closely as practical, using the same server URL protocol and the same WOPI restrictions. Follow the Nextcloud Office configuration guidance to set the Collabora server URL over HTTPS, limit WOPI requests to the Collabora server addresses, and restrict editing to a pilot group. Apply the default format setting in Nextcloud Office, and confirm its exact name and location in the admin manual for your Nextcloud version. Done when a pilot user creates a new text, spreadsheet and presentation file, and each one saves in the chosen format.
Run a representative document set
Assemble a corpus of actual files that your teams exchange, covering templates, forms with fields, tracked changes, spreadsheets with formulas, and decks with embedded media. Open each file in Collabora Online, save it in ODF and in the Microsoft format, then reopen both copies in the Office clients your partners use. Log layout shifts, formula results, lost comments and macro issues for each format. Done when every file has a logged result, and every blocking issue has an owner and a decision on whether it stops go-live.
Communicate the default to users
Send users a short notice that states the default format, the applications affected, the date the change takes effect, and how to save a copy in the other format when a partner requires it. Publish the same guidance on your internal help pages and name a contact for exceptions. Explain which in-progress files should stay in Microsoft format while they are exchanged with partners. Done when the notice has gone to the pilot group first, their questions are answered, and the help page is live.
Roll out in stages and verify saves
Widen access from the pilot group to production in stages, keeping the same group restrictions until each stage has been checked. After each stage, have a sample of new users create files, then confirm in the file properties that the chosen format is stored and that Collabora opens the file without warnings. Keep a documented rollback path, including how you would revert the default and the Office configuration. Done when all intended groups have access and spot checks show new files saved in the chosen format.
Confirm the default holds after rollout
Schedule a recurring check, run after each Nextcloud or Collabora upgrade, that a new document of each type still saves in the chosen format and that partner exchanges still succeed. Review the exception log and ask the policy owner to confirm or retire each request to save in another format. Re-run the representative corpus after upgrades that change office components, since rendering and saving behavior can shift between releases. Done when the first post-rollout check passes and the owner holds a standing record of checks and exceptions.
Security and operational considerations for the format choice
The default format setting is a policy decision, but it sits inside a wider set of controls: who can reach the editor, which servers may call it, how it is patched, and how conversions change files. Each card below covers one of these items so the format decision is reviewed alongside them rather than in isolation.
Restrict WOPI requests by IP
The Nextcloud administration manual recommends limiting WOPI requests to the IP addresses of your Collabora servers, so only your own Nextcloud-to-Collabora traffic can open or save documents. Confirm the list matches your current load balancer and egress addresses after every network change, because a stale allow list breaks editing for everyone. Also use the same protocol for the Collabora server URL as for Nextcloud, preferably HTTPS, so documents do not travel over a weaker channel than the file store.
Limit who can edit
In Nextcloud Office, administrators can restrict which groups may use the editor and which groups may edit rather than only view. Use these group limits to decide who can create or change ODF or OOXML files, especially if a default format change would alter what external partners receive. Review group membership on the same schedule as the format policy, and check that view-only groups cannot save converted copies through other paths.
Patch 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 the branch you run, apply point releases, and verify package signatures during updates. A format policy does not remove the need to patch the document engine that converts and saves every file.
Assess conversion effects on content
Saving a file in the other format is a conversion, and conversions can change layout, styles, comments, tracked changes, fields, macros and document metadata. Illustrative example: a contract template that relies on a Word-specific field may lose the field after a round trip to ODF. Before changing the default, test representative files for content and metadata loss, and decide whether originals must be kept unchanged in their source format for records or legal holds.
Keep an audit trail of policy changes
Record every change to the default format, the editor group limits, the WOPI allow list and the Collabora version, including who approved it, when it took effect and what was tested. Store these records in a system your change process controls, such as version-controlled configuration or your ticketing tool. Auditors and internal reviewers will ask how a format decision was made and whether it was reversed, so the trail should show the rationale as well as the setting.
What teams ask before choosing a default format
How much effort does changing the default format take?
Most of the effort is testing, not the configuration change itself. Switching the default is a setting in Nextcloud Office, but you still need to confirm that your common documents open, edit and save cleanly in the new format. Internal staff usually pay for the time of policy owners, test users and an administrator. A partner adds cost only if you buy fixed-scope testing. Recurring cost depends on your Collabora Online edition: the Collabora pricing page lists the Business plan at 3 euros per user per month for up to 99 users, with Enterprise quoted for 100 or more users. Ask any partner for a quote built from your own test corpus, the number of templates you need to cover and the number of partners who exchange files with you.
How long does a default format change take to roll out?
The duration depends on your test cycle, partner confirmations and communication, and no supplied figure sets a standard length. Plan the rollout in stages: test, pilot with a limited group, then widen access. Pilot groups can be limited in Nextcloud Office, which lets administrators restrict which groups can use the editor and which can edit. Keep the format change separate from any Nextcloud major upgrade. Nextcloud does not allow skipping major releases, requires a backup before every upgrade, and needs third-party apps disabled until they are confirmed compatible. Nextcloud 35 was released on 16 September 2026, and 36 is scheduled for 17 February 2027, according to the Nextcloud release schedule. Check which version you run before you set dates.
What do partners and policy owners need to provide?
Partners and policy owners supply the requirements that decide which format is acceptable. Ask them for a written statement of the formats they accept and any deadlines they set.
- A written format requirement from each external partner, regulator or contract, including whether they accept ODF, Microsoft formats or both.
- A named records or compliance owner who confirms retention, accessibility and signing expectations for each document class.
- Representative sample files from each partner, including the templates they send and receive.
Without these, the test plan rests on assumptions. If your organization handles regulated records, the compliance owner should also confirm whether any external assessor needs evidence of the decision. DeployOpen can plan and run the testing against these inputs, but the requirements must come from your organization and its partners.
Can our internal team change the default format alone?
Your team can change the setting alone if an administrator has access to the Nextcloud Office configuration, which is documented in the Nextcloud admin manual. The harder part is the decision and the evidence behind it. Internal teams often lack a test corpus that reflects real partner files, a documented go or no-go rule, and time from people outside IT, such as legal, records and partner contacts. A reasonable internal approach is to assign one owner for the decision, one for testing, and one for communication, then log every issue found. Bring in a partner when you need an independent test plan, a written record for auditors, or help covering many templates in a short window. Confirm internal capacity before you commit to a date.
What drives format testing effort up the most?
Effort rises with the number of formats, partners and documents that must survive a round trip. Each factor adds test cases and review time.
- The number of external partners, since each may have different expectations for ODF or Microsoft files.
- The number and complexity of templates, especially those with fields, styles, tracked changes, macros or embedded objects.
- Legacy files in older binary or niche formats, which may need separate handling.
- The number of user groups that will edit documents, since each group may use different templates.
- Whether you run several WOPI hosts that open the same documents.
The more of these you have, the larger the test corpus and the longer the sign-off. Use a small sample of each category to estimate your own effort before you ask for a fixed-scope quote.
Does a public sector ODF policy change the work?
A public sector ODF policy can make OpenDocument the required format for some records, and it changes the test plan, but the exact requirement depends on your jurisdiction and body. If a policy applies, testing must cover ODF files created in Collabora Online and opened by Microsoft Office users, plus Microsoft files exchanged with partners who may not accept ODF. The EU Interoperable Europe Act sets interoperability rules at EU level, but it does not by itself settle a default format for your organization. Confirm with your legal and records owners which national, regional or sectoral rules apply, and get that answer in writing before you set the default.
Which Collabora Online version should we test before deciding?
Test on the branch you plan to run in production, because fidelity and fixes can differ between branches. Collabora's 25.04 release notes record that the 25.04 branch was first released on June 19, 2025, and was still receiving point releases in 2026, with 25.04.13 released on September 21, 2026. The 26.04 release was announced on July 23, 2026, and adds an optional AI assistant that is off by default. CODE, the free edition, is a rolling release that Collabora does not recommend for production, so your test results should come from the edition and branch you will operate. Record the exact version in your test report and repeat key tests after each point release.
How DeployOpen scopes a default format decision
DeployOpen scopes the default format decision as a defined piece of work within the client's own infrastructure. That work covers the Collabora Online configuration that determines which formats new documents are created in, the Nextcloud Office settings that expose the editor to users and groups, and the change records that show who approved the default and why. The engineer and the client's owner agree on the systems in scope before any configuration is touched: which Nextcloud instances, which Collabora Online servers, which user groups and which document types. Scope, deliverables and timelines are agreed in writing before work starts, so the client knows what evidence will exist at the end and what it will not cover.
The fidelity testing is where most of the effort sits, and DeployOpen runs it on the client's own documents rather than generic samples. A typical plan takes a representative set of partner-exchanged files, opens and saves them in both candidate formats, and records what changes, including layout, fields, tracked changes and macros. Confirm with the client which external partners send and receive files, and whether those partners can open ODF files without a conversion step. The outcome is a written decision record that names the default, the exceptions, and the owners of each exception. DeployOpen prepares that record and the supporting test evidence, but it does not issue audit reports or certifications, so any compliance reviewer will need to assess the record independently.
Ongoing support after the decision is available as a retainer, which suits organizations that expect to revisit the default when Collabora Online or Nextcloud changes. Ask any partner, DeployOpen included, to state in the written scope who retests after each Collabora Online branch upgrade and who owns the decision if a partner later requires a different format. The retainer scope should name the release branches it covers and the response expectations for format regressions. Those terms are agreed in the same written scope as the initial work, so the client can compare the cost of retesting internally against an external retainer before committing.
