Migrate from Skype for Business Server to Mattermost

Migrate from Skype for Business Server to Mattermost: what moves and what does not

A datacenter-bound team running Skype for Business chat can move the chat and identity layer to self-hosted Mattermost without giving up on-premises control, but the migration is two decisions, not one. The chat-and-identity move is the part Mattermost handles. The meeting decision is separate, because Mattermost is not a drop-in replacement for Skype for Business conferencing. Plan for moderate effort overall, with most of the risk concentrated in re-creating persistent chat rooms as channels and in retiring Edge servers, which carry external federation and remote access that users notice quickly.

Internal IT usually does the bulk of the work, with an implementation partner covering the parts that are hard to staff in-house: the Mattermost deployment itself, the directory integration, the Edge retirement sequence and the cutover runbook. Start by confirming which identity source Mattermost will read. Mattermost SSO and AD/LDAP user sync are listed on its pricing page from the Professional plan, so confirm with Mattermost sales which plan your user count and directory design require. Map Skype for Business groups to Mattermost teams and channels on paper before any data moves, and identify which persistent chat rooms have active members, because those are the only ones worth re-creating.

Be explicit with stakeholders about what does not carry over. Skype for Business presence, federation with partner organizations, and audio, video and web conferencing with desktop sharing will need their own replacement, such as Jitsi, BigBlueButton or a meeting service your organization already licenses. Confirm the chosen meeting service, its dial-in plan and how meeting links reach calendar invites before you switch off the Skype for Business meeting features. Keep both systems running in parallel for a defined window, and set the date for retiring Edge servers only after external partners and remote users have a tested route to the replacement.

Which Skype for Business capabilities map cleanly to Mattermost

This table maps each Skype for Business capability to its Mattermost equivalent and marks it as clean, needs rework or gap. Read the status column first, then check the notes on meetings, telephony and room systems, which Mattermost does not cover. Presence, federation and Edge behavior should be confirmed in your target environment before you commit to a cutover date.

Capability	Mattermost equivalent	Status	What to confirm or plan
Instant messaging	One-to-one direct messages in Mattermost	Clean	Confirm message retention settings match your policy before users move over
Group chat	Group messages and channels	Clean	Map ad hoc group chats to private channels or group messages during the pilot
Persistent chat rooms	Public and private channels	Needs rework	Re-create rooms as channels, assign owners and re-invite members by hand or by script
AD-based identity	AD/LDAP sync in Professional plan and above	Needs rework	Sync requires a paid edition; Team Edition does not include AD/LDAP sync, so confirm the edition you need
Presence	Basic online and away status	Needs rework	Presence behavior differs from Skype for Business; confirm status accuracy and client behavior in your environment
File sharing	File attachments in channels and messages	Needs rework	Confirm file size limits and storage location, and plan shared file storage for high availability clusters
Federation with partners	No direct equivalent in Mattermost	Gap	Partner access needs a separate plan, such as guest accounts or a different platform; confirm with partners
Audio and video meetings	Not provided by Mattermost	Gap	Deploy a separate video service, such as Jitsi, and link meetings from channels
Dial-in telephony and room systems	Not provided by Mattermost	Gap	Requires a separate telephony or conferencing service and room system integration, sized and tested separately
Edge-based external access	No Edge equivalent; reverse proxy and access controls must be designed	Gap	Plan external access, certificates and firewall rules as a new design, then retire Edge servers after cutover

What data and identities can be moved, and what must be rebuilt

Identity and chat content move on different paths. Directory users and groups can be synced automatically, while room history, integrations and bots need a deliberate decision for each item. Work through these cards before you commit to a cutover date, because each one changes the license tier, the import tooling or the staff time.

Active Directory users and groups

Mattermost can sync users from Active Directory through AD/LDAP sync, but this is a paid feature from the Professional plan upward, not part of Team Edition. Confirm that your Skype for Business users map to a single AD OU or group filter, and decide how disabled accounts, service accounts and shared mailboxes are handled. Check that the sync covers the groups you will use for team membership, since group-based channel assignment depends on it.

Single sign-on with SAML or OIDC

Mattermost supports SSO through SAML, OIDC and OAuth, and this is also gated to the Professional plan. Your identity provider, whether AD FS, a federation service or a self-hosted identity product, must issue claims that Mattermost can match to existing accounts. Test login for users with multiple UPNs and confirm how account email addresses are normalized, since mismatches cause duplicate accounts.

Persistent chat rooms as channels

Skype for Business persistent chat rooms do not map one to one onto Mattermost channels, because room roles, moderators and membership rules differ. Inventory each room, its members, and whether it is still active, then create a channel for each room you keep and assign roles manually or through group sync. Archive rooms that nobody has used, and record the decision for each one so that auditors can trace it.

Chat and file history with no documented export

The supplied facts document no Skype for Business export path into Mattermost. Microsoft Teams Export APIs cover Teams content only and do not apply to Skype for Business, so any tool for extracting history must come from your own SQL Server database or a vendor you confirm in writing. Ask whether the tool preserves timestamps, sender identity, attachments and deleted-message flags, and test it on a copy before cutover.

Integrations, bots and call workflows

Skype for Business integrations such as response groups, call routing, room system connectors and custom bots do not carry over to Mattermost. Mattermost offers its own integration model, so each automation needs to be rebuilt as a webhook, slash command or bot, and the owner must be named. List every server-side hook, check which ones are still in use, and assign a rebuild or retirement decision to each.

Retention and evidence records

Before cutover, decide how long Skype for Business message and meeting records must be kept, and where the evidence will live if the old database is decommissioned. Mattermost retention and compliance export are paid features, so confirm whether your plan includes them. Keep a read-only archive of the SfB database with its backup and restore procedure documented, and confirm the retention period with your legal and compliance owners.

The cutover sequence from inventory to decommission

This sequence moves chat from Skype for Business Server to Mattermost in controlled stages, so each group proves its identity, rooms and rollback path before the next group moves and before any Edge server is switched off.

Inventory users, rooms, partners and Edge dependencies
Pull the current Skype for Business user list from Active Directory, along with the persistent chat rooms, their owners and members, and the list of federated and anonymous-access partners that depend on the Edge servers. Record which applications, phones or room systems rely on the front end or Edge. The output is a signed inventory with a room map that lists each room, its owner, its membership source and its target Mattermost channel or team. Confirm each item with the owning business group, because Skype persistent chat rooms are often unowned.
Establish the Active Directory identity baseline
Decide how Mattermost will learn its users. The Mattermost AD/LDAP sync and SSO features are in paid plans, so confirm the plan that includes them and the licensing for the seat count before you commit. Map the AD security groups to Mattermost teams and channels, and test that a disabled AD account loses access. Confirm with your identity team how Mattermost will authenticate, whether through LDAP sync or SAML single sign-on against your federation service. The output is a tested identity design document and a test account set.
Run a pilot group on Mattermost
Choose a small pilot group whose members are willing to report problems. Stand up the Mattermost server in your environment, with PostgreSQL and file storage matching your deployment plan, then create the pilot teams and channels from the room map. Test login, notifications, file sharing, mobile access and retention settings against your policies. Keep a log of defects and a list of features the pilot relies on that Mattermost does not replace, such as telephony or room systems. The output is a signed pilot exit list that names the criteria for expansion and the owner who signs it.
Run a parallel period with Skype for Business for calls
Move chat for the wider group while calls and meetings stay on Skype for Business. Tell users clearly which tool handles which task, and publish the channel names that replace each persistent chat room. Watch for users who keep messaging in Skype out of habit, and track the traffic on both systems to see when Skype chat usage falls. Keep Skype for Business chat history accessible through your existing archiving process, because history does not migrate automatically. The output is a dated record of which groups have moved and a usage report for each system.
Cut over chat and re-create rooms as channels
For each group, disable new Skype chat for the moved users, invite them to their Mattermost teams and channels, and re-create the persistent chat rooms from the room map. Export the rooms' membership and the important history you intend to keep, and load only the content your retention policy allows. Mattermost's Slack migration tooling does not apply directly to Skype data, so plan any history import as a custom task. Record which rooms were re-created, which were archived and which had no owner. The output is a cutover log that matches each source room to its target channel.
Prepare and test a rollback plan
Before you change any production routing, write down how you would return a group to Skype for Business chat: which accounts stay enabled, how the Skype policies are restored, and who has authority to trigger the reversal. Test the rollback on the pilot group, and confirm that messages sent during a rollback window are not lost. The output is a written and rehearsed rollback plan approved by the service owner, with each step tied to a named person.
Move meetings to a video service
Once chat is stable, move scheduled meetings and ad hoc calls to a separate video service such as Jitsi, as covered in the video conferencing guidance. Check how meeting links reach Outlook invitations, which audio and room devices still depend on Skype, and whether external partners need dial-in. Keep Skype for Business meetings running until the last dependent group confirms the replacement works. The output is a list of meeting dependencies with each one marked as moved, replaced or still open.
Retire front end and Edge servers
Retire the Edge servers last, after federation partners are informed, external access is replaced or confirmed unnecessary, and no open dependency remains on the inventory. Decommission the front end pool only after no users or devices depend on it, then remove the DNS records, certificates and firewall rules that served them. Keep backups and configuration records for the period your retention policy requires. The output is a decommission record with a checklist signed by the infrastructure owner, the security team and the service owner.

How to run Skype for Business and Mattermost side by side

Plan coexistence around the identity layer first. Both systems should resolve each person to the same Active Directory account, because Mattermost's AD/LDAP sync and SSO depend on that account and because Skype for Business already trusts it. Move users in waves by Active Directory group, such as a pilot department, then a business unit, then the rest, and keep each wave's group membership stable so sign-in and sync do not change under people mid-move. Mattermost's AD/LDAP user sync is a paid Professional-plan feature, so confirm with Mattermost which tier covers your sync and SSO requirements before the first wave. Confirm your Active Directory synchronization interval and how deprovisioned accounts are handled in Mattermost, since a disabled AD account should lose access on the same schedule as it does for Skype for Business.

Tell users one rule in writing: chat moves to Mattermost channels, and calls and meetings stay on Skype for Business until their wave's meeting migration is complete. Publish the wave calendar, a single page with the Mattermost URL, and a note that old Skype for Business conversations remain readable in Skype for Business but are not copied into Mattermost. External partners need a separate decision. Skype federation with partner organizations ends at cutover unless you keep Edge servers running, so list each partner domain, agree a temporary channel or guest invitation with them, and remove federation only after that partner has confirmed access. Retire Edge servers last, after the final wave has run without external traffic.

High availability is the decision to make before cutover, not after. Mattermost high availability uses redundant application servers, database servers and load balancers, and it is available only on the Enterprise and Enterprise Advanced plans, so a small pilot on Team Edition or Professional will not carry it forward unchanged. Every node in a cluster needs shared file storage, such as Amazon S3, an S3-compatible service or NAS mounted on each node, because local file storage does not work correctly in a cluster and risks corrupting files. Decide the storage design, the database read and search replica plan, and the load balancer topology now, because switching a single-node production instance to a cluster later is a planned change that needs its own window. Ask Mattermost to confirm the licensing tier and the supported deployment topology for your expected user count.

What drives the cost and duration of the move

This table lists the factors that raise or lower the cost and calendar time of moving from Skype for Business Server to Mattermost, and how to reduce each one. Read it as a checklist to scope a quote, since most drivers combine: a large user base with deep AD groups and many persistent rooms multiplies the work. Mattermost prices are not public, so ask for them in writing from sales.

Driver	Why it moves cost or effort	How to keep it down
User count and directory state	Every account must be mapped to a Mattermost user through AD/LDAP sync or SSO, and stale or duplicate AD accounts add cleanup work before cutover.	Clean up disabled and duplicate accounts in Active Directory before the pilot and agree on which OU or group defines who gets access.
Number and type of persistent rooms	Skype persistent chat rooms carry history, owners and moderation settings that must be re-created as channels or teams, and each room needs an owner to confirm it.	Retire inactive rooms, move only rooms with an active owner, and decide early whether archived history is migrated or kept read-only in the old system.
Depth of AD group structure	Nested groups and group-based permissions must be mapped to Mattermost teams, channels and roles, and a flat design is cheaper to map than one with many nested groups.	Document the groups that drive access, flatten where possible, and validate group membership against a pilot team before bulk sync.
SSO integration complexity	Sign-in through SAML or OIDC requires identity provider configuration, certificates and testing, and SSO is included only from the Professional plan.	Confirm the identity provider you will use, decide whether AD/LDAP sync alone is enough, and test sign-in for each client type before cutover.
Mattermost edition choice	Team Edition is free and aimed at teams under 250 users without single sign-on, while Professional, Enterprise and Enterprise Advanced are prepaid annual subscriptions by seat count, priced only through sales.	Match features to requirements first (SSO, AD/LDAP sync, clustering, compliance export, air-gapped use), then request written quotes for the seat count and term you need.
High availability build	High availability requires Enterprise or Enterprise Advanced, redundant application servers, database servers and load balancers, and shared file storage on S3, an S3-compatible service or NAS on every node.	Decide whether you need clustering at all for the first phase, and budget for shared storage and database replicas as separate infrastructure lines with their own owners.
Meeting replacement scope	Skype meetings, dial-in and room systems are not replaced by Mattermost, so each meeting use case needs a video service, a telephony route or a room system decision.	List every meeting type in use, including conferencing with external guests and dial-in, then choose a video service per type before retiring the Skype meeting features.
Edge server retirement	External access, federation and remote user traffic that passes through Edge servers must be re-routed, and partner or guest access paths must be confirmed before the Edge servers are switched off.	Inventory every external user path, move them to the new service first, and keep the Edge servers running until the parallel period shows no remaining traffic.

How the migration changes by estate size and starting point

A single-site estate with a small number of persistent rooms and one Skype for Business front end usually has the simplest path. The main work is deciding which users and rooms carry over, confirming that identity can be read from Active Directory, and moving meetings to a video service. Because the directory is local, directory sync is straightforward, and there is less federation to plan around.

Identity: Confirm how Mattermost will authenticate users. AD/LDAP sync and SSO are paid features on Mattermost Professional and above, so ask whether the Team Edition limits (under 250 users, no SSO) fit your headcount.
Rooms: Inventory persistent chat rooms and map each to a channel or team. Most small estates have fewer rooms than they expect, which keeps this step short.
Meetings: Move scheduled conferencing to a separate video service, since Mattermost does not replace the Enterprise CAL conferencing features.
Edge: Retire Edge servers only after external users have a replacement path, which in a small estate is often a single decision.
Infrastructure: A single node with PostgreSQL is the baseline. Clustering is not needed at this size.

Before cutover, ask your Mattermost partner or Mattermost, Inc. to confirm the current edition limits and which features your user count requires.

What usually goes wrong and how to prevent it

Most failed Skype for Business to Mattermost cutovers do not fail on the server install. They fail on assumptions about history, presence, meetings, directory data, storage and federation. Each card below names one risk, why it matters for this migration, and the check to run before users move.

Assuming Skype history will import

Skype for Business conversation history is stored in its own back-end database and is not part of the Mattermost import path. Mattermost's documented migration tooling targets Slack exports, so plan to keep an archive of Skype history in read-only form. Ask the Skype administrator which retention policy applied and confirm with your records team what must remain searchable for audit before you decommission the old store.

Losing presence-based workflows

Many teams use availability to route calls and questions, and Mattermost shows status but does not replace the telephony and call routing that Skype for Business provided. Before cutover, list every workflow that depends on a green or away indicator, such as escalation paths or help desk handoffs, and redesign each one with channels, mentions or on-call rules. Test them with a pilot group.

Treating Mattermost as a meeting replacement

Mattermost is a chat platform, so audio, video and screen sharing for meetings must come from a separate service. Decide which video service will host meetings, confirm how meeting links will reach calendar invites, and move meetings before users lose their Skype conferencing. Keep Skype meeting capability available until the replacement has been tested with real participants.

AD group drift during coexistence

While both systems run, users may be added to a Skype group or an Active Directory group that Mattermost does not sync, so membership diverges. Mattermost's AD/LDAP sync is a paid feature from the Professional plan, so confirm licensing before you rely on it. Choose one authoritative source for group membership, document it, and reconcile the two lists on a fixed schedule until the old system is turned off.

Shared file storage misconfigured for HA

A Mattermost high availability cluster needs shared file storage on Amazon S3, an S3-compatible service or NAS mounted on every node. Local file system storage will not work correctly and risks corrupting files. Verify the storage path from each application node before go-live, test upload and download from every node, and confirm that backups cover both the database and the file store.

Retiring Edge before federation is confirmed

Skype for Business Edge servers often carry federation and remote access for partner organizations. Switching them off before you know which partners rely on them cuts those conversations without warning. Inventory every federated domain and external user, confirm each partner's plan for the replacement, and only then remove Edge routing. Mattermost does not federate with Skype, so partners need an agreed channel for the transition.

Questions buyers ask before moving from Skype for Business to Mattermost

How much effort and cost should we expect for a move to Mattermost?

Expect the cost to come from people, infrastructure and licensing, and the Mattermost software itself is not the largest line. Team Edition is free and open source, but Mattermost Team Edition is aimed at teams under 250 users that do not need single sign-on, so AD sync and SSO push many estates toward a paid Professional, Enterprise or Enterprise Advanced plan, which Mattermost sells as prepaid annual subscriptions by seat count. Its pricing page lists no public prices, so ask for a quote. Costs that drive the total include the number of seats, whether you need high availability, your database and shared file storage, and the hours your staff or a partner spend on mapping users, rooms and cutover. Remove Windows Server licensing from your own estate only if you retire servers: Windows Server 2025 is licensed per core with a 16-core minimum per server, and Standard and Datacenter both need a Client Access License for each user or device. Ask for a quote that separates one-time work from recurring subscriptions and hosting.

How long does a Skype for Business to Mattermost migration take?

The timeline depends on the number of users, how many persistent chat rooms need recreating as channels, how many meeting workflows must move, and how long you run both systems in parallel. No duration is fixed by the product. A practical plan runs in phases: directory sync and a pilot group first, then channel recreation and user communication, then a cutover by business unit, and finally decommissioning Edge and front end servers. Schedule around your own change windows and any retention or audit obligations for existing Skype messages. Ask any implementer for a written scope with deliverables and dates before work starts, since most engagements are fixed-scope and agreed in writing.

What does our team need to provide during the migration?

Your team needs to supply decisions and access rather than building the platform alone. Expect to provide Active Directory administrators who can approve sync scope and service accounts, a named owner for each business group that uses persistent Skype rooms, a network and DNS owner for the new hostnames, and a database and storage owner for PostgreSQL and shared file storage. Security or compliance staff should confirm how retained chat history and any legal hold requirements will be met before the old system is switched off. Plan time for user communication and a pilot group to test sign-in, notifications and mobile access.

Can our internal IT staff run this migration without outside help?

Internal staff can run it if they have Mattermost administration, PostgreSQL, Active Directory and load balancer skills and the time to do the work during business hours and cutover windows. The main risks are underestimating the directory mapping, the channel recreation effort and the decommissioning of Edge servers, which involves external access, federation and certificate changes. If those skills are thin, a fixed-scope engagement can cover planning, implementation, hardening, backup and documentation, while your team keeps ownership of the live system. DeployOpen plans, implements, integrates, hardens, backs up and documents self-hosted platforms inside your own infrastructure, and it does not issue audit reports or certifications.

Do Mattermost AD sync and SSO require a paid plan?

Yes, for the features most Skype estates depend on. According to the Mattermost pricing page, SSO (SAML, OIDC and OAuth) and AD/LDAP user sync are included from the Professional plan, while high availability clustering and FIPS 140-3 compliance start at Enterprise. Team Edition is aimed at teams under 250 users that do not need single sign-on, so it is not a fit for directory-driven access control. Confirm current plan contents with Mattermost before you commit, because the editions documentation and pricing page are the sources of record.

What happens to our existing Skype chat history?

Skype for Business Server stores chat history in its own database, and Mattermost does not import it automatically. Treat history as a separate project. Options include leaving the old system read-only for a defined retention period, exporting selected conversations to an archive, or migrating only active channels. Mattermost's documented Slack migration path moves users, channels, direct messages, threads and attachments from a Slack export, but that path does not apply to Skype data, so confirm any Skype export method with your implementer and your records team. Retention and legal hold requirements should be settled in writing before you decommission the Skype database.

What should we check in Mattermost high availability before go-live?

Check the shared storage design first. A high availability cluster needs shared file storage on Amazon S3, an S3-compatible service or NAS mounted on each node, and local file system storage will not work correctly and risks corrupting files. High availability requires redundant application servers, database servers and load balancers, and it is available only on Enterprise and Enterprise Advanced plans. Also plan database read replicas and search replicas if concurrent use is high. Test failover and backup restores before cutover, and confirm the design against Mattermost's server deployment planning guidance.

How DeployOpen scopes and runs this migration

DeployOpen is a Chainscore Labs company that plans, implements, integrates, hardens, backs up and documents self-hosted open-source platforms inside your own infrastructure. For a move from Skype for Business Server to Mattermost, we start with a written scope covering directory sync, channel mapping, meeting replacement, Edge retirement and the coexistence period.

How we scope

Inventory which Skype for Business users, persistent chat rooms, federation partners and Edge dependencies must move, and which stay.
Agree in writing how Active Directory groups map to Mattermost teams, channels and SSO or AD/LDAP sync requirements.
Confirm the Mattermost edition, meeting service and hosting model before any work starts, using vendor pricing and support documentation.

How we build

Deploy the Mattermost server, PostgreSQL database and shared file storage in your environment, sized to the scoped user count.
Configure directory sync and login, then test with pilot groups before any production users are moved.
Re-create persistent rooms as channels and test the telephony and room system integrations that Mattermost does not cover.

How we hand over

Document the cutover runbook, coexistence rules, Edge decommissioning steps and rollback criteria agreed with your team.
Deliver configuration records, access model, backup and restore procedures and test results as written handover material.
Walk your administrators through daily operations, upgrade steps and the checks to run after each monthly server release.

How we support

Offer ongoing support, upgrades and continuous testing as a retainer after handover, scoped in writing.
Plan upgrades around the published Mattermost support windows so your team applies supported versions on schedule.
Prepare controls and evidence for compliance assessments, while independent auditors perform any formal audit or certification.

Migrate from Skype for Business Server to Mattermost