How a Microsoft 365 move to Nextcloud, Collabora and OX is structured
The move is three workloads with separate exports and cutovers: files in OneDrive and SharePoint, document editing in Office, and mail and calendars in Exchange Online. Each one needs its own export path, its own target component and its own cutover window. Nextcloud takes the file layer, Collabora Online edits the Office documents inside Nextcloud, and OX App Suite takes Exchange mail and calendars. Teams usually arrive at this structure because of a renewal, a licensing change, a residency requirement or a lock-in concern, and they want each piece to be replaceable on its own terms. The reader's first decision is whether they need all three workloads moved at once or whether one can stay in Microsoft 365 for a period.
IT and platform engineering teams usually run the move, most often with an implementation partner that plans, installs, integrates and documents the stack inside the client's own infrastructure. The internal team owns identity, DNS, mail routing and user communication, and the partner typically carries the Kubernetes deployment, backup configuration and upgrade process. Effort and risk depend less on the number of users than on how many distinct data types, external sharing links, shared mailboxes and custom Office macros the tenant holds. Confirm those counts before asking for a quote, since they drive most of the scope.
OneDrive, SharePoint, Exchange and Office editing each need different tooling, and none of them moves through a single export. Purview eDiscovery can export mailboxes as PST or .msg files and SharePoint and OneDrive content as native documents, but it requires an E3 or E5 license and its search export packages expire 14 days after creation, so the export window has to be planned in advance. Office editing does not move with the files at all: the documents need format testing in Collabora Online for .docx, .xlsx and .pptx, and users must be retrained on the browser editing experience. Treat each workload as its own project plan with its own owner and rollback point.
Which Microsoft 365 capabilities map cleanly and which need rework
This table maps Microsoft 365 workloads to the Nextcloud, Collabora Online and OX App Suite components that would replace them, and marks each row as clean, needs rework or gap. Read the status column first, then the notes on what must be rebuilt or confirmed before cutover. Confirm client and protocol support with each vendor before you commit to a design.
| Capability | Open-source equivalent | Status | What to confirm or rebuild |
|---|---|---|---|
| OneDrive and SharePoint file storage | Nextcloud Files | Clean | Folder structure, file names and sizes map directly. Confirm storage backend and sync client support for your devices. |
| Office document editing in the browser | Collabora Online with Nextcloud | Clean | Confirm .docx, .xlsx and .pptx fidelity for your templates, macros and complex layouts with a test set. |
| SharePoint document libraries and metadata | Nextcloud tags and folder structure | Needs rework | Column-based metadata, content types and library-level permissions usually need redesign as tags, groups or flows. |
| SharePoint version history | Nextcloud file versions | Needs rework | Confirm whether exported version history is preserved and how many versions your retention policy keeps. |
| Exchange mail and calendars | OX App Suite with Dovecot and MariaDB | Clean | Confirm mailbox migration tooling and calendar sharing behavior for your users before pilot. |
| Outlook desktop client | OX App Suite web client, or a third-party client | Gap | Outlook on Windows and Mac relies on Exchange protocols. Confirm which protocols OX supports for your client, and plan user retraining. |
| Desktop Office apps (Word, Excel, PowerPoint) | Collabora Online in the browser, or LibreOffice on the desktop | Gap | Desktop Office add-ins, macros and co-authoring behavior may not carry over. Test each critical workflow. |
| Teams chat, meetings and channels | Nextcloud Talk or a separate chat and video platform | Gap | Teams channels, apps and bots need a separate design. Talk does not replace the full Teams feature set. |
| eDiscovery and legal hold | Export to standard formats with a separate archive | Gap | Purview holds and searches have no direct equivalent. Plan a legal hold process and confirm what evidence auditors will expect. |
| Retention policies | Nextcloud and OX retention settings, configured per platform | Needs rework | Retention rules are set per application. Document each rule and test deletion behavior before go-live. |
How to export mail, files and documents from Microsoft 365
Export is a project step with its own licensing and timing, so plan it before any cutover date is set. Microsoft Purview eDiscovery can export Exchange mailbox items as PST or .msg files, and SharePoint and OneDrive content as native documents with selectable version history. Exporting requires a Microsoft 365 E3 or E5 license, so confirm which licenses are assigned to the administrators and eDiscovery managers who will run the export. Search export packages expire 14 days after creation, which means a package that is not downloaded and staged in time must be regenerated.
Before running an export, confirm with your Microsoft 365 administrator which retention policies, litigation holds and sensitivity labels apply to each mailbox and site. Holds can keep items that users have deleted, and retention settings can affect what a search returns, so the export scope may differ from what users expect. Decide whether version history is needed for every document or only for current versions, because that choice drives the volume of data you must move. Record the search query, the date, and the person who ran each export so the transfer can be traced later.
On the receiving side, plan to import PST files into Open-Xchange only after confirming the import method your OX App Suite deployment supports, and load SharePoint and OneDrive files into Nextcloud through a tested sync or bulk import path. Run one pilot mailbox and one document library end to end, compare item counts and file sizes, and check permissions and version history on the target. The confirmation of tenant licenses, retention rules and the target import tooling should be written into the migration plan before the first full export is requested.
What data and integrations must be moved or rebuilt
Moving from Microsoft 365 to a Nextcloud, Collabora Online and OX App Suite stack means four data sets and one set of integrations, each with its own export path and its own owner. Mail and calendars, files with their version history, user identities, and browser-based Office editing all need a decision before cutover. The Outlook and Teams integrations are the part most often underestimated.
Mailboxes and calendars
Exchange Online mailboxes move to OX App Suite through an IMAP or migration path you define and test, since the mail platform is a separate component from Nextcloud. Purview eDiscovery can export mailbox items as PST or .msg files, but exporting requires an E3 or E5 license and search export packages expire 14 days after creation. Plan a dated export window and confirm with Open-Xchange how calendars, contacts and shared folders are imported and how folder permissions survive the move.
OneDrive and SharePoint libraries
Nextcloud takes over OneDrive and SharePoint files, but version history does not carry across automatically. Export native documents with selectable version history through Purview, then decide which versions to import and how library permissions map to Nextcloud folders, groups and share links. Check file names, path lengths and unsupported characters before import, because mismatches are the most common reason a bulk upload fails.
User identities and sign-in
Nextcloud's LDAP app lets Active Directory or LDAP users appear in Nextcloud and sign in with directory credentials. Nextcloud also documents OpenID Connect and SAML user authentication backends, and OX App Suite supports OpenID Connect. Choose one identity source of truth before migration, confirm group mapping for both platforms, and test how Entra ID-based accounts will be re-linked to the new directory.
Browser editing through WOPI
Word, Excel and PowerPoint files open in the browser through Collabora Online, which connects to Nextcloud using the WOPI protocol. Test .docx, .xlsx and .pptx files with macros, tracked changes, comments and embedded objects, since fidelity differs from desktop Office. For production, confirm the Collabora edition, the load balancer rule that routes by the WOPISrc parameter, and that all users editing one document reach the same pod.
Outlook and Teams integrations
Outlook add-ins, the Outlook desktop sync experience and Teams meeting and chat links have no direct equivalent in this stack and must be rebuilt or replaced. Nextcloud documents Outlook and Teams integrations for Enterprise subscribers, so confirm which ones your tier includes. Inventory every add-in, shared mailbox workflow and Teams channel used for files, then decide what users will use instead before the cutover date is set.
Cutover order: inventory, pilot, parallel run, cutover and decommission
This sequence moves mail, files and documents from Microsoft 365 to self-hosted components in a controlled order, so each workload is verified before users depend on it and the old tenant is retired only after its data is confirmed elsewhere.
Inventory mailboxes, sites and identities
The migration team lists every mailbox, shared mailbox, mail-enabled group, SharePoint site, OneDrive account and Teams-linked file store, and records owners, sizes, retention needs and legal holds. Identity owners map each user to a directory account that Nextcloud and OX App Suite will authenticate against, typically through LDAP or Active Directory, OpenID Connect or SAML. The output is a signed-off inventory spreadsheet with one row per workload and a named owner for each. Confirm with your legal and records teams which holds apply before any export starts, because the export method you choose depends on them.
Build the target environment and upgrade path
The platform team deploys Nextcloud, Collabora Online and OX App Suite v8 in your own infrastructure, using the supported database, cache and storage versions listed in each vendor's requirements. Nextcloud installations start on the current major release, and every future upgrade must go one major version at a time with a full backup taken before each upgrade. Disable third-party apps until they are confirmed compatible with the target version. The output is a staging environment with a documented upgrade runbook, tested backups and restore evidence.
Run a pilot with a small user group
Select a pilot group that covers different roles, such as a finance user, an executive with a shared mailbox and a project team with large document libraries. Migrate their mail, calendar, files and document editing into the staging environment, then test sync clients, sharing links, Collabora editing of .docx, .xlsx and .pptx files, and mobile access. Compare item counts and file checksums against the source export. The output is a pilot report listing defects, workarounds and a go or no-go decision for the wider waves.
Migrate in waves with a parallel run
Move users in waves while Microsoft 365 remains the system of record. Export mailboxes and SharePoint or OneDrive content through Purview eDiscovery, note that exporting requires an E3 or E5 license and that search export packages expire 14 days after creation, then import them into OX App Suite and Nextcloud. Repeat delta syncs for changes made during the parallel period. The output for each wave is a reconciliation record showing item counts, folder structure, version history and failed items, and a list of users whose data is confirmed in the new platform.
Cut over files, then mail
Move file storage first, because document links and Collabora sessions are easier to verify in isolation, then cut over mail and calendars. Freeze new writes for each wave, run a final delta sync, update DNS MX and autodiscovery records, point client profiles to the new services, and confirm that inbound mail is delivered and outbound mail is signed correctly. Keep the Microsoft 365 tenant readable during this window. The output is a cutover checklist per wave, signed by the workload owner, with a rollback plan that names who can reverse the DNS change.
Hold the source tenant in read-only state
After all waves are cut over, keep the Microsoft 365 tenant for a retention period that your legal and compliance owners set, and place it in read-only or restricted mode so no new data is created there. Monitor the new platform for missed mail, failed syncs and user tickets. Retain a verified archive export in a location your records policy covers. The output is an archive register that records what was exported, where it is stored, who can access it and when it will be destroyed.
Decommission Microsoft 365 workloads
Once the retention period ends and the archive is verified, remove licenses, delete mailboxes and sites that are no longer needed, revoke app registrations and connectors, and remove DNS records that pointed to Microsoft 365. Update the backup scope so the self-hosted systems are covered by the same recovery objectives as before. Document the final state in the runbook. The output is a decommissioning record confirming that no workload remains in Microsoft 365 and that the self-hosted stack has an active backup and upgrade schedule.
How the move differs by size and starting point
Small teams with light Exchange use usually have a few hundred mailboxes or fewer, modest file estates and little custom configuration. The move is mostly about choosing a deployment size and cutting over in a short window. Collabora Business is priced for up to 99 users, while Nextcloud Enterprise tiers start at a 100-user minimum, so headcount alone can decide which support model fits.
- Support model: Below 100 users, Collabora Business is the paid option referenced in the pricing page, and Nextcloud Enterprise is not available at that size, so confirm which support path you will rely on before choosing the edition.
- Mail scope: Light Exchange use often means a few shared mailboxes and standard calendars, which keeps the export and import workload small.
- Single deployment: A single-node or small-cluster install is usually enough, but confirm the current Nextcloud and Collabora system requirements for your size.
- Cutover: A short, scheduled cutover with a clear freeze window is often easier to run than a phased plan.
- Admin skills: Expect one or two people to run the stack, so document backups and upgrade steps early.
Before committing, ask a vendor or partner to confirm how support and maintenance terms apply to your user count and growth plans.
Large mailbox estates raise the work on the mail side: more data to export, more migration waves and more dependencies on Exchange features. Mailbox size, archive policies and the number of shared or resource mailboxes drive most of the effort. Plan the mail workload as its own track, with its own cutover sequence, rather than folding it into the file migration.
- Export path: Purview eDiscovery exports mailbox items as PST or .msg files, but search export packages expire 14 days after creation, so schedule exports in batches that match your import capacity.
- Wave planning: Group users by department or mailbox size and move one wave at a time, keeping coexistence routing in place until each wave is verified.
- OX App Suite sizing: Persistent data such as PIM attachments needs a distributed file system, and the choice between NFS and object storage depends on scale, so confirm this early.
- Compliance holds: Confirm how legal holds and retention labels are represented in the export, because they may not carry over as-is.
- Licensing: Exporting through eDiscovery requires an E3 or E5 license, so confirm that licensing is still active during the export window.
Ask for a written inventory of mailbox sizes, archives and shared mailboxes before setting the wave count.
Organizations with existing Active Directory already have users, groups and password policies in place. The main question is how identity flows into Nextcloud and OX App Suite, and whether the directory stays the source of truth during the move. Identity design decides which accounts can log in on day one, so settle it before migrating any content.
- LDAP connection: Nextcloud's LDAP app lets Active Directory users appear in Nextcloud and log in with their directory credentials, which keeps the user list aligned with the directory.
- Other login methods: Nextcloud also documents OpenID Connect and SAML backends, which may suit organizations that already run an identity provider in front of AD.
- OX authentication: Check the OpenID Connect and SAML options for OX App Suite against your identity provider before choosing a login path.
- Group mapping: Map AD groups to Nextcloud groups and OX roles early, because permissions on shared folders and calendars depend on them.
- Account lifecycle: Confirm how leavers and disabled accounts are handled so mailboxes and files are not left orphaned.
Ask your directory team to document the attributes and groups each service needs, then test login with a pilot group before any content moves.
Organizations with heavy SharePoint co-authoring rely on many people editing the same Office documents at once. Collaborative editing depends on the document server, the file platform and the load balancer working together, so this tab focuses on the editing layer rather than storage. The priority is keeping a document on one editing session while many users work in it.
- Editing backend: Collabora Online integrates with Nextcloud through WOPI and edits .docx, .xlsx and .pptx files in the browser.
- Routing: The Collabora Helm chart README states that load balancers must route by the WOPISrc parameter so users editing one document reach the same pod, and horizontal pod autoscaling is disabled because scaling breaks collaborative editing.
- Sizing: The chart recommends production limits of 8 CPU cores and 8000 MiB of memory per pod, with requests of 4 cores and 6000 MiB, so plan capacity against your peak editing load.
- Format fidelity: Test complex Word and Excel files, macros and tracked changes against real samples, because layout differences are common.
- Desktop apps: Confirm which users still need desktop Office for advanced features, since browser editing does not cover every case.
Ask for a load test plan that uses your own document types and concurrent editor counts before setting replica numbers.
What drives cost and duration in this migration
This table lists the main factors that raise or lower the cost and calendar time of moving from Microsoft 365 to Nextcloud, Collabora Online and OX App Suite. Read each row as a driver, why it matters, and how to keep it down. The main takeaway is that data volume, identity design and Kubernetes platform work usually matter more than the software licenses.
| Driver | Why it matters | How to keep it down |
|---|---|---|
| Mailbox volume and attachments | Exchange Online mailboxes must be exported through Purview eDiscovery as PST or .msg files, then imported into OX App Suite. Large archives, long retention and heavy attachments increase export time, storage on the NFS or object backend, and the number of import passes. | Inventory mailbox sizes before scoping. Migrate in waves, archive or purge data that is out of retention, and move archive mailboxes separately. |
| File volume and version history depth | SharePoint and OneDrive content can be exported as native files with selectable version history. Keeping every version multiplies the data to copy and the storage Nextcloud must hold. Export packages also expire 14 days after creation, which forces re-runs for large sets. | Agree a version retention rule with business owners. Export current versions for most libraries, keep full history only for regulated records, and plan export batches inside the 14-day window. |
| Identity integration | Nextcloud's LDAP app and its OpenID Connect and SAML backends must match existing directory users, groups and sharing rules. Mapping errors cause duplicate accounts, broken permissions and re-work after cutover. | Decide the identity source before build. Map groups and attributes in a pilot tenant, and use one directory for Nextcloud and OX App Suite logins. |
| Number of concurrent Office editing sessions | Collabora Online keeps each document on one pod, and the Helm chart says autoscaling is disabled because scaling breaks collaborative editing. Peak editing load therefore drives manual replica counts and resource limits, which the chart recommends at 8 CPU cores and 8000 MiB per pod for production. | Measure peak concurrent editors from Microsoft 365 usage reports. Size replicas for peak, not average, and use WOPISrc-based routing so each document stays on one pod. |
| Kubernetes and Istio platform work | OX App Suite v8 runs on Kubernetes with Helm 3.17.0 or newer and requires Istio, unless the basic ingress-nginx option is used. Redis 7.4.x, MariaDB and the cluster itself add build and operations effort before any user data moves. | Reuse an existing supported cluster where possible. Confirm the Kubernetes and Istio versions against the OX support commitment, and document the platform as code so it can be rebuilt. |
| Storage backend choice | OX Drive and PIM attachments need a distributed file system: NFS for small to mid-size deployments, or object storage such as S3, Ceph RadosGW or Scality RING for larger ones. Object storage adds capacity planning and licensing that NFS does not. | Size storage from the mailbox and file inventory. Start with the backend your team already runs, and confirm capacity growth with the storage vendor or internal platform team. |
| Enterprise subscription for Nextcloud | Nextcloud Hub is free under AGPL, but Nextcloud Enterprise has a 100-user minimum. List prices from the Nextcloud pricing page start at 71.29 euros per user per year for Standard, 104.99 for Premium and 204.75 for Ultimate, for 100 or more users, with lower rates from 200 users. This is a recurring cost that scales with headcount and the tier chosen. | Compare the tiers against the support hours and maintenance lifecycle you need. Ask Nextcloud GmbH for a quote at your exact user count, and check whether a self-supported deployment meets your risk appetite. |
| Collabora Online support plan | The Collabora Business plan is listed at 3 euros per user per month for up to 99 users on the Collabora Online pricing page, and includes long term support, an SLA and signed security updates. CODE is free but Collabora does not recommend it for production, so a production deployment usually needs a paid plan or self-supported ownership. | Confirm whether signed security updates and an SLA are required by your controls. Ask Collabora for a quote for the number of users in scope. |
| Support retainers and ongoing upgrades | Nextcloud requires one major version upgrade at a time with a backup before each, and OX App Suite LTS releases have a fixed support window. Recurring upgrade, patch and testing effort continues after cutover and is separate from the subscriptions above. | Plan a recurring upgrade calendar from the Nextcloud release schedule and the OX support commitment. Ask for a fixed-scope or retainer quote that covers upgrades and testing for the full year. |
What usually goes wrong and how to prevent it
Most failed Microsoft 365 exits fail on timing, licensing or version drift rather than on the software itself. The cards below cover the risks that tend to surface in the export, upgrade and cutover steps of this stack, with a prevention step for each.
Export packages expire
Purview eDiscovery search export packages expire 14 days after they are created. If a team generates a package for mailboxes and then waits for the downstream import to be scheduled, the package can lapse before anyone downloads it. Build the export and the download into one change window, record the package creation date, and regenerate any package that is close to expiry before the OX import begins.
Missing E3 or E5 export licenses
Exporting through Purview eDiscovery requires a Microsoft 365 E3 or E5 license for the administrator performing the export. Organizations on Business plans often discover this only when the export button is unavailable. Confirm the license assignment for the exporting account before the project plan is signed off, and ask your Microsoft partner or account team to confirm which export paths your tenant can use.
Skipped Nextcloud major releases
Nextcloud does not allow skipping major releases during upgrades, so an instance several versions behind must move through each intermediate major version in turn. Teams that install the latest release from a stale template or old backup can end up with a version they cannot upgrade in one step. Pin the target version in the runbook, take a backup before every upgrade, and disable third-party apps until each is confirmed compatible.
Collabora scaling that breaks co-editing
The official Collabora Online Helm chart disables horizontal pod autoscaling because scaling breaks collaborative editing and copy and paste. Replicas are set manually, and the load balancer must route by the WOPISrc parameter so everyone editing one document reaches the same pod. Test with several users on one document during load testing, and confirm that your ingress (Nginx, HAProxy or OpenShift Router) honors this routing before go-live.
Unsupported OX release versions
Open-Xchange supports a standard release for 12 weeks, and an LTS release until the next LTS plus six months. Deploying a release that has already left support, or one that will leave support during the rollout, creates a patching gap for mail. Choose the current LTS line as the baseline, check the support commitment for the date of every version you deploy, and schedule the upgrade path before the cutover rather than after it.
Identity mismatches between directories
Users who exist in Entra ID, in Nextcloud and in OX App Suite under different login names or different primary addresses will see missing files, orphaned calendars and failed sign-ins after cutover. Nextcloud can bind to LDAP or Active Directory, and it also supports OpenID Connect and SAML, but each path needs a single agreed unique identifier. Map users before any mail or file migration, and reconcile aliases, shared mailboxes and group membership in a dry run.
Questions buyers ask before moving from Microsoft 365
What does a move from Microsoft 365 to a self-hosted stack cost, and what drives it?
The cost depends on scope, user count, data volume and who does the work, and no single figure applies. Expect four components: the infrastructure you run (compute, storage, database, backup), the software subscriptions you choose (Nextcloud Hub is free to self-host, while Nextcloud Enterprise is sold per user with a 100-user minimum, and the Collabora Online Business plan is listed at 3 euros per user per month for up to 99 users), the migration labor, and the ongoing operations. Costs that recur include infrastructure, subscriptions and operations, while migration is largely one-time. Ask any vendor or partner for a written quote that separates these components, and confirm current list prices directly with Nextcloud pricing and Collabora before budgeting.
How long does a migration from Microsoft 365 take?
Duration depends on mailbox volume, the size and structure of SharePoint and OneDrive content, the number of integrations, and how many workloads move in each wave. No fixed timeline applies to every tenant. Plan the work in phases: pilot users first, then file migration, then mail and calendar, then a cutover per group. Export tooling also sets limits you must plan around. Purview eDiscovery search export packages expire 14 days after creation, so exports must be downloaded and processed within that window. Your engagement scope and milestones should be agreed in writing before work starts, with timelines tied to your own volumes.
What does our team need to provide during the migration?
Your team needs to supply decisions and access, not only infrastructure. Typical inputs include an owner for each workload, a list of users and groups for directory mapping, the retention and legal hold rules that apply to mail and files, the Microsoft 365 licenses and roles needed for exports, and a window for user communication and training. For Nextcloud, you will also need a database, object or file storage and a backup target. For OX App Suite v8, the platform runs on Kubernetes with Helm 3.17.0 or newer, requires Istio or a basic ingress-nginx option, uses Redis 7.4.x and MariaDB, and needs a distributed file system such as NFS or object storage. Confirm your Kubernetes and storage skills, or budget for them, before choosing an architecture.
Can our own IT team do the migration without an implementation partner?
Yes, many teams can, provided they have Kubernetes, identity, mail and storage skills in-house and time to run a pilot. The harder parts are mail coexistence, directory integration, large file migrations and upgrade discipline. Nextcloud does not allow skipping major releases, so each upgrade must go one major version at a time, with a backup before every upgrade and third-party apps disabled until confirmed compatible. Open-Xchange also has a defined support commitment for standard and LTS releases that your team must track. A partner such as DeployOpen can plan, implement, integrate, harden and document the stack under a fixed-scope agreement, and can provide ongoing support as a retainer. Compare that against your team's capacity honestly.
How does coexistence work between Microsoft 365 and the new stack during the move?
Coexistence means both environments run side by side for a period, with users, mail and files moving in groups. Plan routing for inbound and outbound mail, calendar free/busy visibility where it matters, and single sign-on so users do not manage separate passwords. Nextcloud's LDAP app and its OpenID Connect and SAML backends let directory users sign in with existing credentials, and OX App Suite documents OpenID Connect and SAML options as well. Test each group before cutover, and keep a rollback path for mail delivery. Confirm exact coexistence features and limits for your Microsoft tenant and OX version with the vendors and your implementation plan.
What happens to Outlook and Teams users after the move?
Outlook users need a supported path to the new mail and calendar service, and this is the question most often underestimated. OX App Suite provides its own web and mobile interfaces for email, calendar and tasks, so users change applications rather than keep Outlook as-is unless a compatible connector is confirmed for your version. Nextcloud Hub, by contrast, does not include a mail server, so mail must be covered by another component. Teams has no direct equivalent in this stack, so chat and meeting workloads need a separate plan under the team chat and video conferencing pages. Train users on the new interfaces before cutover, and confirm each client compatibility claim with the vendor.
Can we drop Microsoft 365 licenses during the parallel run?
Not until every workload you need has been migrated, verified and retired from Microsoft 365, and until you have completed any exports that require a license. Purview eDiscovery export of mailboxes and SharePoint or OneDrive content requires a Microsoft 365 E3 or E5 license, so keep the license that covers export until those exports are complete and validated. Removing a license may also delete or restrict access to mailbox and file data according to Microsoft's retention terms, so review those terms with Microsoft before you reduce seats. Ask Microsoft in writing which licenses and retention periods apply to your tenant at each step.
How DeployOpen scopes and runs this migration
DeployOpen plans, implements, integrates, hardens, backs up and supports the stack inside your own infrastructure, whether that is your cloud accounts, your data centers or an air-gapped network. For this migration that means the Nextcloud Server and its database, the Collabora Online deployment that serves Office documents, and the OX App Suite on Kubernetes with its Istio or ingress layer, Redis, MariaDB and the distributed file store behind OX Drive and PIM attachments. Engagements are fixed-scope. Before work starts, the scope, deliverables and timelines are agreed in writing, so each workload (files, documents, mail and calendars) has a named owner, an acceptance test and a cutover step you can check.
Expect the written scope to settle a few decisions early: which Nextcloud tier you need (community or an enterprise subscription with a 100-user minimum), how many Collabora replicas are needed given that load balancers must route by the WOPISrc parameter, which user authentication backend connects to your directory, and how the export packages from Microsoft 365 are validated before the tenant is decommissioned. Ask for the test plan covering document round trips in .docx, .xlsx and .pptx, and for the backup and restore evidence produced before each Nextcloud major upgrade, since Nextcloud requires one major version at a time.
Retainers cover ongoing upgrades, patch windows, monitoring-driven support and continuous testing after the cutover. DeployOpen prepares systems, controls and evidence for compliance assessments, but it does not issue audit reports, attestations or certifications. Those come from independent auditors and certification bodies, so ask your auditor early which evidence they will request from the migration, such as access reviews, backup restore tests and change records, and make that list part of the written deliverables.
How DeployOpen runs the migration
DeployOpen is a Chainscore Labs company that plans, implements, integrates, hardens, backs up, documents and supports self-hosted open-source platforms inside your own cloud accounts, data centers or air-gapped networks. For a move from Microsoft 365 to Nextcloud, Collabora Online and Open-Xchange, we set the cutover order for files, documents and mail, then build and hand over each component in your environment.
How we scope
- Inventory which Exchange mailboxes, OneDrive and SharePoint libraries, and document formats are in use today.
- Confirm the Microsoft 365 license tier and whether Purview eDiscovery export access is available to the team.
- Agree user counts, storage sizes, identity source and cutover order in a written, fixed-scope document before work starts.
How we build
- Deploy Nextcloud, Collabora Online and OX App Suite in your environment, with database, cache and object or file storage sized to the written scope.
- Connect the directory and single sign-on to the target platforms and test with a pilot group of users.
- Test document fidelity for .docx, .xlsx and .pptx files and confirm mail, calendar and sharing behavior before any production cutover.
How we hand over
- Document the architecture, configuration, upgrade path and backup and restore procedures for your own operations team.
- Provide a cutover runbook covering export, import, user communication and rollback steps for each workload.
- Walk through the handover with your administrators and record the export evidence needed for your own records.
How we support
- Offer ongoing support, upgrades and continuous testing as a retainer after the migration is complete.
- Plan upgrades one Nextcloud major version at a time, with backups taken before each change.
- Confirm the support terms you need for Collabora Online and OX App Suite releases with the vendors before you commit to a plan.
