What to install after Office LTSC 2021 end of support
No single replacement fits every desktop, so the choice is made device by device. Office LTSC 2021 support ended in October 2026, which means affected machines no longer receive security updates, and any renewal or upgrade decision should be made now. The four options are Office LTSC 2024, Microsoft 365 Apps, LibreOffice, or browser-based editing with Collabora Online. Each path differs in licensing, lifecycle and how much of the existing Office workflow it keeps. Before you commit, confirm the support end date and lifecycle terms for each exact product on Microsoft's lifecycle pages, because end dates differ by product and channel.
The decision usually turns on four factors. First, macros: list which workbooks and documents use VBA. LibreOffice uses Basic macros, keeps Microsoft VBA macros when a file is edited there, and can run some Excel VBA scripts if that option is enabled, so heavy macro users may need to stay on Office. Second, Outlook: LibreOffice does not replace Outlook, so users who depend on it need an Office license or another mail client. Third, offline needs: installed applications work without a network connection, while Collabora Online needs a reachable server. Fourth, file exchange: test real documents from outside partners, because LibreOffice help notes that converted files need manual reformatting in proportion to their complexity, and pivot tables, conditional formatting and revision marks may not convert cleanly.
Work the device list into groups before buying anything. Sort machines by which of the four factors they meet, pilot a small group from each group, and record what breaks. Browser-based editing suits users who mostly edit documents and share them through a platform such as Nextcloud, and Collabora Online 26.04, announced July 23, 2026, includes an optional AI assistant that is off by default. If you choose LibreOffice, note that 26.2 is supported until November 30, 2026, while 26.8.1 arrived on October 2, 2026 as the first maintenance release of 26.8, so plan both the branch you deploy and its upgrade path. Organizations that need service levels should ask LibreOffice ecosystem partners about enterprise builds, because The Document Foundation does not provide technical support.
What the end of support requires from each desktop
Office LTSC 2021 reaches end of support in October 2026, so each desktop needs a decision before its security cover stops. The six requirements below apply whichever option you choose, from Office LTSC 2024 or Microsoft 365 Apps to LibreOffice or browser-based editing. Work through them for each device group, starting with the groups that open the most external files.
Security patches stop
Once support ends, Microsoft no longer issues no further security updates for the Office LTSC 2021 build, so any flaw found later stays open on every desktop still running it. Documents from outside senders are a common route in, which makes this the most time-sensitive requirement. Before the cutoff, list which devices run the build, confirm what your endpoint tooling reports for it, and set a replacement date for each device group.
Open and save Office files
Partners, clients and regulators will keep sending Word, Excel and PowerPoint files, so the replacement must open and save them. LibreOffice opens and saves docx, xlsx and pptx files, and administrators can set a Microsoft format as the default save format under Load/Save options. Test a sample from each department in both directions before choosing a default for that group.
Check complex files first
Conversion is not a perfect copy. LibreOffice Help says converted files may need manual reformatting in proportion to their complexity, and it names AutoShapes, revision marks, OLE objects, pivot tables, conditional formatting and some formulas as features that may not convert cleanly. Build a test set from financial models, contracts with tracked changes and board decks, then record which files need rework and who signs off on each.
Macros and templates
LibreOffice's own macro language is Basic, so VBA code must be inventoried and tested before any desktop changes. VBA macros are kept when a file is edited in LibreOffice and run again in Office, and some Excel VBA scripts can run in LibreOffice if that option is enabled. Ask each business owner which macros are business critical, which templates depend on them, and whether they must run on the replacement desktop.
Outlook is a separate decision
The office suite does not replace Outlook, so mail and calendar need their own decision. Identify which devices connect Outlook to an on-premises Exchange server, because Microsoft points customers from Exchange Server 2019 to Exchange Server SE or Exchange Online. Confirm the mail and calendar path for each group before retiring the Office build on the same device.
A named owner per decision
Each device group needs one named owner who approves the replacement, the test results and the rollout date. LibreOffice's own guidance recommends enterprise builds from ecosystem partners for large organizations, because The Document Foundation does not provide technical support. Ask any candidate supplier who answers for security fixes, which SLA applies, and how long the chosen branch stays supported.
Which option meets which requirement
This table compares the main replacements for Office LTSC 2021 on affected desktops, showing how each one meets the end-of-support requirement and what it costs in trade-offs. Read each row against the devices you are deciding about, since Outlook and Office macros often decide the outcome. The main takeaway is that LibreOffice and Collabora Online can reduce license renewals, but they still need mail, macro and server work.
| Option | How it meets the end-of-support requirement | Trade-offs |
|---|---|---|
| Office LTSC 2024 | Same desktop apps and Outlook on a volume license. Confirm its support dates with Microsoft. | Still a Windows desktop suite on recurring licensing. Lifecycle details must be confirmed before purchase. |
| Microsoft 365 Apps | Subscription desktop apps that include Outlook. Confirm the lifecycle and update channel with Microsoft. | Recurring per-user subscription. Some features depend on Microsoft cloud services and an identity tenant. |
| LibreOffice desktop | Writer, Calc, Impress, Draw, Base and Math cover Word, Excel and PowerPoint work. Current release is 26.8.1, released October 2, 2026. | Outlook is not replaced. Complex files need manual reformatting, and LibreOffice uses Basic macros, so VBA macros need review. |
| LibreOffice enterprise build | Ecosystem partner builds with long-term SLAs and technical support for large deployments. | The Document Foundation does not provide technical support. Partner fees recur, so ask for a written quote. |
| Collabora Online in the browser | Edits docx, xlsx and pptx in the browser through a WOPI host such as Nextcloud. | Needs a WOPI host and servers. The Business plan is 3 euros per user per month for up to 99 users, per Collabora's pricing page. |
| Outlook and mail | No option above replaces Outlook. Keep Office LTSC for mail or plan a separate mail migration. | Mail, calendar and Outlook add-ins need their own decision, pilot and testing. |
How well LibreOffice handles Office files and macros
LibreOffice opens and saves .docx, .xlsx and .pptx files, so most documents from an Office LTSC 2021 desktop can move without a format conversion project. An administrator can set a Microsoft format as the default save format under Load/Save options, which keeps users from silently creating ODF files that colleagues on Office cannot open. Decide that default before the pilot, because it determines what recipients receive. The LibreOffice Help page on converting Microsoft Office documents states that converted files need some manual reformatting in proportion to their complexity, so plan review time by document class rather than assuming a clean round trip.
The features that most often fail to convert cleanly are AutoShapes, revision marks, OLE objects, pivot tables, conditional formatting and some formulas. Check your estate for these before committing. Inventory the heavy Excel workbooks first: finance models, reports built on pivot tables, and sheets with conditional rules or embedded objects. Open each one in LibreOffice Calc, recalculate, compare results with the Office original, and record every cell or chart that changes. Involve the workbook owners in that comparison, since they can spot a wrong total faster than a generic test script.
Macros need a separate decision. LibreOffice uses Basic rather than VBA, so Office VBA macros are kept when a file is edited in LibreOffice and run again in Office, but they will not run in LibreOffice unless the Excel VBA option is enabled and the script is one LibreOffice can handle. Confirm this against the LibreOffice Help guide on Microsoft Office compatibility for your version. List every macro-driven workbook and template, classify each as retire, rewrite in Basic or keep in Office, and keep Office licenses for the users whose work depends on the ones you keep.
Which path fits each type of desktop
Staff who mainly write documents and build slides need a desktop editor that opens and saves Microsoft formats reliably. LibreOffice Writer and Impress are the usual candidates for this group, and organizations that want a support contract can look at enterprise builds from LibreOffice ecosystem partners. The main risk is layout drift in branded templates and complex slides, not basic editing.
- Likely option: LibreOffice Writer and Impress, with Microsoft formats set as the default save format where recipients need them.
- Main risk: Converted files may need manual reformatting in proportion to their complexity, according to LibreOffice Help.
- Features to test: AutoShapes, revision marks, embedded OLE objects and custom slide masters.
- Support model: The Document Foundation does not provide technical support, so confirm whether a partner build is needed.
- Scope of the pilot: Choose the most-used templates and the longest decks from each team and convert them as a sample.
Check that branded templates and in-use decks open and print the same way in LibreOffice as they do in the Office originals before choosing this path.
Finance and analytics users depend on formulas, pivot tables and VBA macros, so this group needs the most testing. LibreOffice Calc handles many workbooks well, but its macros use Basic rather than VBA, and that difference drives the decision. Treat macro-driven workbooks as a separate project from the general desktop rollout.
- Likely option: LibreOffice Calc for workbooks without macros, with a separate pilot for macro-enabled files.
- Macro behavior: LibreOffice keeps Microsoft VBA macros when it edits a file and runs them again in Office. It can run some Excel VBA scripts if that option is enabled, so treat this as partial coverage.
- Pivot tables and formatting: Pivot tables and conditional formatting are on LibreOffice's list of features that may not convert cleanly.
- Formula fidelity: Some formulas may not convert cleanly, so reconcile totals against the Excel originals.
- External data: Connections to databases, add-ins and linked workbooks need their own test.
Inventory every macro-enabled workbook, then run each one through its normal close cycle in a test copy and compare the outputs with Excel before any Office licenses are retired.
LibreOffice does not replace Outlook, so any desktop moving off Office LTSC still needs a plan for mail and calendar. Groupware such as OX App Suite provides email, calendar, documents, drive and tasks, and can be deployed on premises, in a public cloud or as the managed OX Cloud service. Mail and calendar are a separate migration from the document editors, with their own risks.
- Likely option: A groupware suite such as OX App Suite in your own infrastructure, with document editing handled by a separate editor.
- Main risk: Outlook features tied to Exchange, such as shared mailboxes, delegation and add-ins, may not have direct equivalents. Confirm each one.
- Client access: Confirm which web, mobile and desktop clients users will need, and whether some users still need Outlook.
- Existing Exchange servers: Exchange Server 2019 extended support ended in October 2025, so on-premises Exchange 2019 mailboxes already sit outside vendor support.
- Data export: Confirm how mail, calendar and retention data will be exported and kept for legal holds.
List every mail flow, calendar sharing and retention requirement, and confirm in writing with the groupware provider that each one is covered before moving any mailbox.
Users who mostly open documents from a file platform can edit them in the browser, without a desktop suite. Collabora Online edits .docx, .xlsx and .pptx files and connects to file platforms such as Nextcloud through the WOPI protocol. This path reduces desktop installs but moves more weight onto the server and the platform team.
- Likely option: Collabora Online inside Nextcloud or another WOPI host, using a paid edition for production.
- Edition choice: CODE is the free development edition and is not recommended for production, so plan for the Business or Enterprise edition or confirm the support route.
- Plan pricing: Collabora's pricing page lists the Business plan at 3 euros per user per month for up to 99 users, and the Enterprise plan is quoted for 100 or more users.
- Scaling: The official Helm chart disables horizontal autoscaling, sets replicas manually and requires the load balancer to route by WOPISrc, so confirm the platform team can run it.
- Format limits: Browser editing has the same conversion limits as LibreOffice for complex files.
Count the users who would edit in the browser, compare that number with the plan thresholds, and run a pilot with the teams that edit most often before setting the cluster design.
Devices on offline or restricted networks often depend on Office LTSC because it needs no cloud service. LibreOffice can be installed from an internal package repository, and Collabora Online can run on an internal server where browser editing is needed. The main constraints are update delivery, approved software sources and the exchange of documents with outside parties.
- Likely option: LibreOffice installed from an internal repository on desktops, with Collabora Online on an internal server for browser editing.
- Updates: No vendor update path reaches an isolated network, so mirror releases internally and test each maintenance release. The Document Foundation says production users can stay on LibreOffice 26.2, which it supports until November 30, 2026, so confirm which branch your mirror tracks.
- Support: The free builds come with community support only, so confirm an enterprise support route for critical or classified networks.
- Document exchange: Files from outside arrive in Microsoft formats, so agree conversion and output rules with the parties you exchange with.
- Licensing: Office LTSC activation and license server dependencies go away, but record the license terms of every replacement component.
Confirm with your security authority which software sources, update methods and hosting locations are approved before selecting any option for these devices.
How to roll out the chosen option device by device
This sequence moves each affected desktop or browser user off Office LTSC 2021 in controlled stages, so every device lands on a supported option with documents, macros and users checked first. The result is a signed-off pilot, a packaged build and a retirement record for each Office LTSC 2021 install.
Inventory devices, documents and macros
The IT team lists every device with Office LTSC 2021 installed, the users on each, and the shared templates, add-ins and macros those users depend on. For Excel and Word macros, record which files use VBA, because LibreOffice uses Basic macros rather than VBA and some Excel VBA scripts run only if an option is enabled. Done when each device has an owner, a usage profile and a macro list that the pilot team can review.
Classify each device against the decision path
Assign every device to one branch: Office LTSC 2024 or Microsoft 365 Apps where Office must stay, LibreOffice for desktop editing, or browser-based editing with Collabora Online for users who work mainly in a hosted file platform. Devices that need Outlook must keep a mail client, since LibreOffice does not replace Outlook. Done when each device record has one chosen branch and a named reason, reviewed by the security and business owners.
Pick the LibreOffice version branch
Decide whether production desktops run LibreOffice 26.8, which The Document Foundation lists as the latest stable release with 26.8.1 available, or stay on the 26.2 branch. The Document Foundation said production users can stay on 26.2, which is supported until November 30, 2026, so confirm the support window that applies to your organization before fixing a version. Organizations that need SLAs and security updates for several years should confirm the enterprise build from an ecosystem partner. Done when the approved version and its support end date are written into the standard build record.
Stand up Collabora Online for browser users
For browser editing, deploy Collabora Online with Docker images, system packages or Kubernetes, using the free CODE image only for testing, since Collabora does not recommend CODE for production. Horizontal pod autoscaling is disabled in the official Helm chart because scaling breaks collaborative editing and copy and paste, so set replicas manually. Configure the load balancer to route by the WOPISrc parameter so everyone editing one document reaches the same pod. Start from the chart's recommended production limits of 8 CPU cores and 8000 MiB of memory per pod, with requests of 4 cores and 6000 MiB, and validate those values under your own load. Done when two users can co-edit one document through the chosen WOPI host and sessions stay on one pod.
Pilot with heavy Excel and macro users
Move a small group of heavy Excel users and the owners of macro-dependent files to the chosen option. Open a sample of production workbooks and documents, check formulas, conditional formatting, pivot tables, revision marks and any AutoShapes or OLE objects, since LibreOffice Help says these may need manual reformatting in proportion to complexity. Log each defect with its file and the fix applied. Done when the pilot group signs off that the business-critical files work and the open defects have owners and agreed workarounds.
Package and deploy through policy
Build a standard installer or image for the approved desktop option and deploy it through your device management tool, setting Load/Save options so the default save format matches your standard, either ODF or a Microsoft format. For browser users, publish the Collabora Online endpoint through the host platform. Confirm the update channel and who approves each update. Done when a test device passes the standard build check and a pilot device opens, edits and saves the agreed formats without manual steps.
Train users and retire Office LTSC 2021 after sign-off
Run short training on the new applications, the save format default, macro behavior and how to report a broken file, and keep a help desk runbook that covers the known conversion issues from the pilot. Once the pilot is signed off, remove Office LTSC 2021 from devices in waves, keep a few licenses where a documented need remains, and record each uninstall against the device inventory. Done when the inventory shows no Office LTSC 2021 installs outside the approved exception list and each exception has a named owner.
What evidence to keep for the device decisions
Each device decision needs a paper trail that an independent auditor or internal risk owner can follow from inventory to configuration. The six records below connect the choice made on each desktop to the testing, sign-off and licensing behind it. Independent auditors judge whether this evidence is sufficient; DeployOpen prepares the records but does not certify them.
Device inventory with chosen path
A row per desktop or user group, listing the installed Office build, the chosen path (Office LTSC 2024, Microsoft 365 Apps, LibreOffice or browser-based editing), the owner and the decision date. Keep it current after each wave, because the inventory is the first thing an auditor samples. IT asset management owns it, and the security or risk owner reviews it. Confirm the device list against your directory and endpoint management tools, not a spreadsheet alone.
Macro and template inventory with test results
A list of every VBA macro, add-in and template in use, with the result of running each one in the target application. LibreOffice Help notes that Basic macros replace VBA and that converted files need manual reformatting, so this inventory shows which documents still depend on Office behavior. Business application owners sign off on the results, and the power user group runs the tests.
Pilot sign-off record
The written acceptance from the pilot group, covering the documents tested, the formats exchanged with outside parties, the print and template checks and any open defects with their owners. The sign-off should name the business unit that accepts the residual risk. Project sponsor and the department head hold this record, and it should exist before any wider rollout begins.
Retired and retained Office license record
A ledger of every Office license retired at the device change and every license kept for a named use, such as an external exchange that still needs Office or a machine running a line-of-business add-in. Record the license type, holder, and the reason for keeping it. Procurement and software asset management own this record, and finance uses it to confirm that renewals match actual use.
Support contract or enterprise build records
Proof of the support arrangement behind the open-source office suite, such as a LibreOffice enterprise build from an ecosystem partner or a Collabora Online Business subscription. Keep the contract, service levels, the security update channel and the version in production. LibreOffice in business states that The Document Foundation does not provide technical support, so a named support path is what the risk owner needs to see. Procurement owns the contract, and IT operations owns the version record.
Change record for the browser deployment
Versioned records of the Collabora Online configuration, including the WOPI host integration, ingress rules, replica counts and the AI assistant setting if it is enabled. The Helm chart README says load balancers must route by the WOPISrc parameter, so routing changes belong in this record with a test result attached. The platform engineering team owns the change log, and the security team approves changes that touch data flow.
Questions buyers ask before choosing a path
What drives the cost of each path away from Office LTSC 2021?
The cost driver is different for each path. Office LTSC and Microsoft 365 Apps are paid through licenses, and LibreOffice is free to download but its enterprise build carries a support contract. Browser-based editing with Collabora Online adds a per-user subscription on top of the server you run. Every path also carries one-time work (inventory, template rework, pilot, training) and recurring work (updates, help desk time, patching the servers you host). Ask each vendor or partner for a quote that separates licenses, support, testing, training and help desk time so the paths can be compared on the same basis.
How much does Collabora Online Business cost per user per month?
According to the Collabora Online pricing page, the Business plan costs 3 euros per user per month for up to 99 users. It includes long term support, a service level agreement, signed security updates and customer portal access. For 100 or more users, the Enterprise plan is quoted with volume discounts and adds integration support, customization services and roadmap input. Remember that this subscription sits alongside the hosting cost of the Collabora server and the platform that calls it, such as Nextcloud, so confirm both before comparing with Office licenses.
Can LibreOffice replace Outlook for email and calendars?
No. LibreOffice includes Writer, Calc, Impress, Draw, Base and Math, but it does not provide email or calendar functions, so Outlook needs its own replacement. Teams usually pair LibreOffice for documents with a groupware platform such as OX App Suite or openDesk for mail and calendars. Plan that second workstream separately, because it has its own mailbox migration, client configuration and user training.
How long does a device-by-device rollout take, and what changes the duration?
No fixed duration applies to every organization, so treat any single estimate with caution. The main drivers are the number of macros and templates that need rework, the number of devices and user groups, and how broad the pilot is. Heavy Excel users with VBA-dependent workbooks take longer to move than users who only write letters. Ask any provider for a timeline built from your own inventory of macros, templates and device counts, with a defined pilot group and exit criteria before wider deployment.
What does the work need from our IT staff?
Your staff own the decisions and the access. They need to inventory installed Office versions, identify users who depend on VBA macros, choose the default save format and approve the pilot group. They also need to manage packaging and deployment through your software distribution tool, confirm which document formats external partners use, and run the help desk during cutover. For a browser-based option, the platform team must run and patch the hosting, load balancing and storage. Confirm these responsibilities in writing before you choose a path.
Can our own team carry out the migration without a partner?
A capable internal team can handle a small, document-focused rollout, especially if the macro inventory is short. The work becomes harder when Excel workbooks rely on VBA, when conversions need manual reformatting because of complex AutoShapes, pivot tables or revision marks, or when you host browser-based editing for many users. LibreOffice Help notes that converted Microsoft Office files need some manual reformatting in proportion to their complexity. Assess your own skills honestly, and set a written scope if you hire outside help.
Why is CODE not suitable for production use?
CODE, the Collabora Online Development Edition, is free and released roughly once a month as a rolling release. Collabora describes it as suited to testing, home use or small teams, and not recommended for production. For production, the paid Business or Enterprise plans add long term support, a service level agreement and signed security updates. If you are weighing a free build against a supported one, the difference lies in patch timing and support accountability, not only the license fee.
When should we bring in an implementation partner?
Bring in a partner when the rollout touches many devices, a large macro estate, a browser-based editing platform, or a regulated environment that needs documented controls. DeployOpen plans, implements, customizes, integrates, hardens, backs up, upgrades, documents and supports self-hosted open-source platforms inside your own infrastructure. Most engagements are fixed-scope, with scope, deliverables and timelines agreed in writing before work starts, and a quote follows from that written scope. DeployOpen prepares evidence for compliance assessments but does not issue audit reports or certifications.
How DeployOpen plans and implements the switch
DeployOpen works through Office LTSC 2021 end of support by scoping the device groups, applications and documents that need a decision, then building and testing the chosen path in your own infrastructure. Engagements are fixed-scope, with deliverables and timelines agreed in writing before work starts.
How we scope
- Inventory Office LTSC 2021 desktops by department, noting Outlook, macro and add-in dependencies for each group
- Record which document types, templates and VBA macros must open unchanged in the replacement suite
- Agree in writing which devices move to LibreOffice, Office LTSC 2024, Microsoft 365 Apps or browser editing
How we build
- Set up a pilot group with heavy Excel and template users to test real files before any wide rollout
- Package the chosen suite and default save formats for deployment through your existing software management tools
- Document macro conversion results and reformatting work so the remaining gaps are known before users reach them
How we hand over
- Deliver a device-by-device decision register with the reason behind each choice and its owner
- Provide runbooks for installation, updates, file format defaults and rollback for each suite in use
- Train help desk staff on the known differences in layout, formulas and macros that users will report first
How we support
- Offer ongoing support, upgrades and continuous testing as a retainer after handover
- Confirm with each vendor whether a support contract or enterprise build is needed for your environment
- Review the decision register as Office and LibreOffice release branches change, and agree the schedule in writing
