Open-Xchange vs Zimbra: which to choose

Open-Xchange or Zimbra: when each one fits the email suite decision

OX App Suite fits best when you run email and groupware for other organizations. Hosting providers, telcos and ISPs that need a white-label suite, and teams comfortable running Kubernetes, are the audience OX builds for. OX positions the product for on-premises, public cloud or its managed OX Cloud, and v8 is delivered as Helm charts on a cluster that also needs Istio or a basic ingress-nginx option. Zimbra fits better when you already run a Zimbra estate, need Outlook integration, ActiveSync mobile sync or archiving and discovery, and already hold a license key for Zimbra Collaboration Daffodil version 10. The decision turns on four things: licensing risk, scale, migration effort and who supports each platform.

Licensing risk is the first thing to pin down in writing. Zimbra's download page states that a new V10.1 license key is required to run the product, and its core server is described as open source while high-availability clustering, encryption and large-scale sync sit behind a commercial license. Zimbra's FOSS build is not shipped as packages. The zm-build repository contains scripts that you compile yourself, so budget engineering time for that path. OX publishes AGPL-3.0 mirrors of appsuite-frontend and appsuite-middleware, but those mirrors do not replace a commercial agreement. OX's Operations Guide notes that certain modules or features may carry custom packaging, limitations or separate fees set in the license agreement, so ask which features your deployment needs are covered by that agreement.

Confirm scale, migration and support before you shortlist either suite. OX lists NFS for small to mid-size deployments and object storage such as S3 or Ceph RadosGW for larger ones, plus MariaDB and Redis as core dependencies, so ask your OX partner to size the storage tier against your mailbox count. Check Zimbra's release dates against your upgrade plan: Zimbra 10.0 reached end of general support on June 30, 2025, and Zimbra 10.1.0 is the current line. Ask each vendor for its support scope, response commitments and upgrade path in writing, and map the migration of existing mailboxes, calendars and shared folders as a separate, costed workstream.

Which platform fits which scenario

This table maps common buying scenarios to the platform that usually fits better and the condition that drives the choice. Read each row against your own hosting model, licensing position and team skills, because the better fit changes when those conditions change.

Scenario	Better fit	Condition that drives the choice
Hosting provider running multi-tenant email and groupware	OX App Suite	OX App Suite is positioned for hosting providers, telcos and ISPs as a white-label platform, so the provider's branding and tenant model matter more than a single-company install.
Enterprise on-premises replacement of an internal mail system	Depends on scale and team	Confirm with each vendor whether the features your size needs (clustering, encryption, large-scale sync) sit in the paid tier, and whether your team can operate a Kubernetes-based stack or a packaged server.
Existing Zimbra estate facing a license renewal	Evaluate both, starting with a migration plan	Zimbra 10.1 needs a license key, so the cost of staying is clear. Compare the migration path, support windows and the effort to move mailboxes and calendars before deciding.
Small team wanting a self-compiled FOSS build	Zimbra (zm-build route) for those comfortable compiling	Zimbra's zm-build repository holds scripts for a FOSS build that users compile themselves, so the work and ongoing maintenance stay with your team.
Kubernetes-averse IT department	Neither suits this profile without outside help	OX App Suite v8 is designed for Kubernetes with Helm charts and Istio, while the Zimbra FOSS route requires compiling your own build. Confirm which operating model your team can support.
Organization that needs a vendor to run the platform and carry support	OX App Suite (confirm terms)	Ask Open-Xchange which support tiers and service agreements apply to your deployment, because some modules may be subject to separate fees in the license agreement.
Team that values a publicly mirrored UI and middleware codebase	OX App Suite	Open-Xchange publishes appsuite-frontend and appsuite-middleware mirrors under AGPL-3.0, which makes the source easy to review, though feature licensing still follows the agreement.

How OX App Suite v8 and Zimbra are built and run

OX App Suite v8 and Zimbra take very different paths to the same outcome: a mail and groupware platform that users can rely on. OX App Suite v8 is a Kubernetes workload with its own data and storage dependencies, while Zimbra is a server stack whose advanced clustering sits behind a commercial license. The cards below set out what each design asks of your platform team after go-live.

Helm charts on Kubernetes

OX App Suite v8 is designed to run on a Kubernetes cluster and is delivered as Helm charts that reference container images. Helm 3.17.0 or newer is required. Your team owns the cluster, upgrades and image pipeline, so the question to settle early is whether you already run Kubernetes in production and who on staff can operate it. Zimbra is installed as a server stack on hosts you manage, which removes that dependency but shifts patching and scaling into different tooling.

Kubernetes N-1 and N-2 support

OX App Suite v8 supports the two Kubernetes minor versions behind the current one, which sets your upgrade cadence for the cluster. Confirm the exact versions in the current requirements before you pick a distribution, and plan Kubernetes upgrades as part of suite upgrades rather than as separate projects. Zimbra has no equivalent dependency, so an OX deployment adds a cluster lifecycle that a Zimbra deployment does not.

Istio or ingress-nginx

OX App Suite v8 requires Istio, supporting the latest Istio release plus two prior versions. Where Istio cannot be used, a basic ingress-nginx option exists. This choice matters because the service mesh adds its own certificate, traffic policy and upgrade work. Ask whether your organization already operates Istio, and if not, whether the ingress-nginx path meets your security and high-availability requirements before you commit.

Redis 7.4.x for caching and sessions

OX App Suite v8 uses Redis 7.4.x for caching and session storage. It is deployed by default through the littlered operator, and unmanaged or custom Redis setups can be configured instead. Confirm whether your platform team will run the operator or connect to a Redis service you already maintain, and who handles failover and patching for it. Zimbra's session handling sits inside its own server stack, so this is an extra component to own on the OX side.

MariaDB with InnoDB and Galera

OX App Suite v8 uses MariaDB with the InnoDB storage engine as its primary data store. Supported versions are 10.6.x, 10.11.x, 11.4.x and 11.8.x, and Galera Cluster is supported for high availability. Check the version line against your database standards before you size the cluster, and confirm backup and restore procedures for a Galera setup. Zimbra manages its own mailbox storage model, so the database operations skill set you need differs between the two platforms.

Distributed file system for mailbox data

Persistent data such as OX Drive files and PIM attachments must sit on a distributed file system. NFS is the stated fit for small to mid-size deployments, while object storage such as AWS S3, Ceph RadosGW or Scality RING is the stated fit for larger ones. Storage choice drives backup design, restore time and cost, so size it before you buy hardware. Zimbra's commercial high-availability clustering and large-scale sync are the Zimbra counterpart, and you should compare what each storage model means for your recovery targets.

Zimbra server and commercial clustering

Zimbra states that its core server is open source, while high-availability clustering, encryption and large-scale sync are available through a commercial license. Zimbra 10.1 needs a license key, and its download page offers Zimbra Collaboration Daffodil version 10. Ask Zimbra or your reseller which features your scale requires and whether clustering is included in the tier you are quoted. Day-two work then depends on that license, since losing or lapsing it affects the features your operations rely on.

Capability comparison from supplied facts

This table compares licensing, source access, deployment models, clustering, encryption, Outlook and ActiveSync, archiving, identity and release support for OX App Suite and Zimbra Collaboration. Where the supplied facts do not answer a question, the cell names what to confirm with the vendor. Treat any open gap as a question for the written quote, not as a missing feature.

Capability	Open-Xchange OX App Suite	Zimbra Collaboration
License and source	AGPL-3.0 source mirrors for appsuite-frontend and appsuite-middleware on GitHub. Module use may carry separate fees set in the license agreement.	Core server described as open source. The download requires a V10.1 license key, and advanced features need a commercial license.
Build and source path	Public mirrors give access to source code. Confirm what a full buildable release contains and how updates are delivered.	The zm-build repository holds scripts for a FOSS build, with examples for 10.1.0 and 10.0.8. Users compile it themselves, and no ready FOSS packages are offered.
Deployment models	On premises, public cloud, or the managed OX Cloud, according to ox.io. Confirm which model suits your data residency needs.	On-premises, private cloud or regional data center, according to zimbra.com. Confirm whether Zimbra offers a managed service of its own.
High-availability clustering	Version 8 is designed for Kubernetes with Helm charts and supports Galera Cluster for MariaDB. Confirm the high-availability design for the mail and storage tiers.	High-availability clustering is listed as a commercial license feature.
Encryption	Not covered by the supplied facts. Confirm encryption at rest and in transit, and key management, with Open-Xchange.	Encryption is listed as a commercial license feature. Confirm which controls the license includes.
Outlook and ActiveSync	Not covered by the supplied facts. Confirm Outlook client support, ActiveSync coverage and supported client versions with Open-Xchange.	Outlook integration and ActiveSync mobile sync are Professional tier features.
Archiving and discovery	Not covered by the supplied facts. Confirm archiving, legal hold and search export options with Open-Xchange.	Archiving and discovery are Professional tier features.
Identity options	OpenID Connect and SAML operator documentation is published for OX App Suite. Confirm the versions your identity provider needs.	Not covered by the supplied facts. Confirm supported SSO protocols and directory integration with Zimbra.
Release support window	Standard releases are supported for 12 weeks. LTS releases run until the next LTS plus six months, and v8.47 is the current LTS.	Zimbra 10.0 reached end of general support on June 30, 2025. Zimbra 10.1.0 reached general availability on July 16, 2024, and the current patch is 10.1.21.

What the license and paid editions actually cover

Open-Xchange publishes mirrors of the App Suite user interface and middleware on GitHub under the AGPL-3.0 license, including the appsuite-frontend and appsuite-middleware repositories. That gives you the source for the code those mirrors contain. It does not, on its own, settle which modules you may use, because Open-Xchange's Operations Guide states that the right to use certain modules or features may be subject to custom packaging, limitations or separate fees set in the license agreement.

Source mirrors: The AGPL-3.0 mirrors cover the frontend and middleware code Open-Xchange publishes on GitHub.
Module rights: Some modules or features may be packaged, limited or priced separately in your license agreement, so read the agreement, not only the repository.
Standard release support: A standard release is supported for 12 weeks, ending with the availability of the third following release.
LTS support: An LTS release is supported until the next LTS release plus six months. v8.35 was the first v8 LTS and is now discontinued, and v8.47 (FCS 2026-03-18) is the current LTS.
Newest listed release: The support commitment lists v8.53, with first customer shipment on 2026-09-23.

Before you commit, ask Open-Xchange in writing which modules your deployment needs are covered by the license, which are separately priced, and which LTS line your support will run on. OX Support Commitment is the natural starting point for the support questions.

What drives running cost on each side

Running cost for either suite is mostly people and infrastructure, with license terms deciding what is paid for and when. The cards below separate one-time migration work from recurring cost, and list what to ask for in a written quote before comparing totals.

Licence and subscription fees

Zimbra 10.1 requires a license key, and its advanced features such as high-availability clustering, encryption and large-scale sync sit behind a commercial license. OX App Suite is licensed through a commercial agreement with the service provider, and its AGPL-3.0 source mirrors do not by themselves give you a supported product. Ask each vendor which features your design needs, whether fees are per user, per server or per tenant, and whether renewal terms are fixed in the quote.

Kubernetes, Istio and cluster footprint

OX App Suite v8 is delivered as Helm charts for a Kubernetes cluster, and Helm 3.17.0 or newer is required. Istio is required where it can be used, with ingress-nginx as a basic alternative, so the platform team must run and patch that stack. Zimbra runs on conventional servers, so its infrastructure cost is less tied to a container platform. Ask for the sizing and node count the vendor assumes and who maintains the cluster after go-live.

Storage backend and database cluster

OX App Suite stores OX Drive files and PIM attachments on a distributed file system, with NFS for smaller deployments and object storage such as AWS S3, Ceph RadosGW or Scality RING for larger ones. Its primary data store is MariaDB with InnoDB, and Galera Cluster is supported. These are recurring infrastructure costs that grow with mailbox and attachment volume. Ask which storage tier and database topology the quote assumes, and whether backup and restore for both tiers is in scope.

Staff skills and operating effort

Running OX App Suite well needs people who can operate Kubernetes, Istio, Redis, MariaDB and a distributed file system together. Zimbra administrators need Zimbra-specific skills, and a FOSS build of Zimbra Collaboration must be compiled from zm-build rather than installed from a package. Each path shifts cost between salaries, contractors and vendor support. Ask who on your side owns each layer and what the quote includes for handover and runbooks.

Upgrade cadence and release windows

Support windows set how often you must upgrade. Open-Xchange supports a standard release for 12 weeks and an LTS release until the next LTS plus six months, with v8.47 as the current LTS. Zimbra 10.0 reached end of general support on June 30, 2025, so a Zimbra 10.0 estate has already moved past its support window. Each upgrade carries testing and change effort that recurs for the life of the platform. Ask which release line the quote covers and how many upgrade cycles it includes.

Paid modules and vendor support

Open-Xchange's Operations Guide says some modules or features may carry custom packaging, limitations or separate fees set in the license agreement. Zimbra's Standard and Professional tiers add features such as Outlook integration, ActiveSync mobile sync and archiving and discovery. These fees are often one-time setup plus recurring subscription. Before comparing totals, ask for an itemized list of every module your users need, and confirm which items are priced separately.

Moving users from Zimbra to OX App Suite, in order

This sequence moves mailboxes, calendars, contacts and shared folders from a Zimbra server to OX App Suite in controlled waves, so each group is verified before the next one moves and the old server can be retired with a documented fallback.

Inventory accounts, data and retention rules
Your mail or messaging team lists every Zimbra account, distribution list, shared calendar, shared folder and resource, then records the size of each mailbox and any retention or archiving rules that apply to it. Confirm which Zimbra features your organization actually uses, such as ActiveSync, Outlook connectivity or archiving and discovery, because each one needs a matching plan on the target side. The step is done when the inventory is signed off by the business owners who will judge the migrated data, and every sharing rule is written down rather than remembered.
Stand up and validate the target platform
Your platform team deploys OX App Suite in your own infrastructure, which for v8 means a Kubernetes cluster installed from Helm charts, with Istio or the basic ingress-nginx option, Redis 7.4.x, a supported MariaDB version and a distributed file system for stored files and attachments. Before any user data arrives, the team tests login, mail flow, calendar invitations, file storage and backup and restore on a non-production instance. The step closes when a test account can send and receive mail, share a calendar and recover a deleted item, and the version choice is confirmed against the Open-Xchange support commitment.
Plan identity integration and DNS cutover
Your identity team decides how users sign in to OX App Suite, using the OpenID Connect or SAML options described in the Open-Xchange documentation, and maps directory groups to the right access. In parallel, the mail team plans MX, autodiscover and client endpoint changes, lowers DNS record time-to-live values in advance, and prepares a rollback record. The step is complete when a written cutover plan names each DNS change, its owner, its timing and the exact rollback action, and the identity mapping has been tested with a small set of accounts.
Rebuild client profiles and mobile configurations
Because client settings do not move with the mailbox, the desktop, mobile and Outlook-facing configurations must be redesigned for the new platform. Your end-user support team documents each client type in use, confirms which protocols the target supports for that client, and writes the setup guide and certificate handling steps. Confirm with Open-Xchange how each client connects in your chosen configuration before promising users a particular experience. The step is done when a pilot user can configure each client type from the guide without help from the migration team.
Run pilot groups and verify migrated data
A small pilot group, drawn from IT and a few business units, is migrated first using the migration tooling, after the vendor confirms how it handles mail, calendars, contacts, folders and permissions for your Zimbra version. Compare item counts, folder structure, shared calendar permissions and recent messages between source and target, then collect written feedback from pilot users over a set working period. The step is complete when the pilot shows no unexplained data loss, every gap has a documented fix, and the business owners approve moving the next wave.
Migrate remaining users in waves
The remaining accounts move in groups sized so the support desk can absorb questions, starting with lower-risk departments and finishing with shared mailboxes and high-dependency teams. For each wave, the team freezes changes where needed, runs the final synchronization, performs the DNS cutover from the plan, and reconciles counts and permissions before closing the wave. The step produces a wave log that records accounts moved, exceptions and rebuilt sharing rules, and it is done when every wave has a signed reconciliation.
Retire the Zimbra server with a retained archive
Once all waves are reconciled, the old server stays read-only for a retention period set by your legal and records teams, and a final archive of mail, calendars and configuration is taken and stored under your retention policy. Only then are Zimbra services stopped, licenses or support agreements ended, and DNS and certificate records for the old server removed. Ask Synacor and your internal records team to confirm what license or support obligations remain during the read-only period. The step is complete when the archive is verified restorable and the decommissioning record is signed by the owners.

Where OX and Zimbra projects usually run long

Plan for the platform build before anyone thinks about user cutover. An OX App Suite v8 deployment is designed to run on a Kubernetes cluster and is delivered as Helm charts that reference container images, with Helm 3.17.0 or newer required. Your team must also settle the Istio question early: the requirements call for Istio, supporting its latest release plus two prior versions, and a basic ingress-nginx option exists only where Istio cannot be used. Redis 7.4.x (deployed by default through the littlered operator, or custom if you prefer), MariaDB with InnoDB in one of the supported 10.6.x, 10.11.x, 11.4.x or 11.8.x lines, and a distributed file system for OX Drive files and PIM attachments (NFS for small to mid-size deployments, or object storage for larger ones) all need owners and sign-off. Identity integration, through OpenID Connect or SAML depending on your directory, belongs in the same first phase.

Zimbra projects tend to stall on different decisions. Before installation, confirm licence provisioning: the Zimbra download page states that a new V10.1 license key is required to run Zimbra Collaboration Daffodil version 10. If you want a FOSS build instead, Zimbra's zm-build repository provides scripts that users compile themselves rather than download as packages, so your build pipeline, patch ownership and test cycle become your responsibility. For scale, the core server is open source, but high-availability clustering, encryption and large-scale sync sit in the commercial licence, so ask the vendor in writing which features your target size depends on and plan the cluster topology before the first mailbox moves.

Four delay points recur on both sides. Identity federation often takes longer than the mail platform itself, because directory attributes, aliases and group membership need to match what clients expect. Client reconfiguration is slow because each mail client, mobile device and calendar profile must be re-pointed, and some users will need help. Data volume during migration drives timelines more than mailbox count: measure total mailbox and attachment size per site, and test a full sync at that volume. Change control adds weeks when maintenance windows, rollback criteria and approval gates are not agreed up front. Before you fix scope in writing, confirm the Kubernetes and Istio support matrix with Open-Xchange, the licence terms and feature list for your size with Synacor, the Zimbra patch level you will run, and who signs off on each of these items in your own environment.

Questions buyers ask before choosing between OX and Zimbra

What does an OX or Zimbra replacement cost, and what drives it?

The cost depends on the scope agreed in writing, not on a list price. Open-Xchange sells OX App Suite through its own channel and the license agreement can set custom packaging, limitations or separate fees for certain modules, so ask for each one by name. Zimbra's core server is open source, but high-availability clustering, encryption and large-scale sync sit behind a commercial license, and the Professional tier adds Outlook integration, ActiveSync and archiving. The main drivers are user count, the number of modules you need, the hosting platform, data volume, and whether you use a self-built Zimbra FOSS build. DeployOpen does not publish a price list. A quote follows from a written scope that separates one-time work (planning, migration, hardening, documentation) from recurring work (support, upgrades, retainers), and it should name the licensing you still need to buy from the vendor.

How long does an email suite migration take?

The timeline is set by the amount of mail and calendar data, the number of mailboxes, the directory and identity integration, and how much cutover coordination your users can accept. Other drivers are the source platform version, the target architecture, and how many custom integrations must be rebuilt. OX App Suite v8 is delivered on Kubernetes with Helm charts, Istio or an ingress-nginx option, Redis 7.4.x and MariaDB, and persistent data on NFS or object storage, so infrastructure readiness can take as long as the mail move itself. Zimbra 10.1 on the other hand is a single product with a known installer path. Ask any provider for a phased plan with written milestones, a pilot group, rollback steps and a dated cutover window before you accept a timeline.

What does our team need to provide for the project?

Your team provides the decisions and access that no outside party can make for you. That includes a named business owner, an identity source for users and groups, DNS and certificate control, a hosting environment in your own cloud, data center or air-gapped network, and storage capacity that matches the backend you choose. Engineers need Kubernetes and database administration skills if you run OX App Suite v8, or Linux and Zimbra administration skills if you run Zimbra. Security reviewers need to approve the access model, backup targets and retention rules. Put these responsibilities into the written scope so each side knows what it owns during the migration and afterward.

Can our own IT team migrate users without a partner?

Yes, many teams do this in-house, but the answer depends on your team's experience with mail migration, directory integration and the target platform. Zimbra's zm-build repository includes scripts for a FOSS build, but those scripts produce a build you compile yourself, so the work of testing, patching and supporting that build stays with you. Open-Xchange publishes AGPL-3.0 mirrors of appsuite-frontend and appsuite-middleware, yet the mirrors do not replace the documented deployment, the Helm charts or the support commitment. A common approach is to do the migration internally with a partner covering the risky steps, such as cutover, hardening and runbooks. Whichever route you choose, confirm the support boundary before you start.

How does licensing risk differ between OX App Suite and Zimbra 10?

The main difference is where the licensing terms sit. OX App Suite publishes AGPL-3.0 source mirrors, but Open-Xchange's Operations Guide says the right to use certain modules or features may depend on custom packaging, limitations or separate fees in the license agreement. Zimbra 10.1 requires a new license key to run the Daffodil release, and Zimbra says its advanced features need a commercial license. Read the license agreement, the module list and the terms that apply on renewal before you commit. Ask each vendor, in writing, which components you can run without a key, which need one, and what happens to your deployment if the key or agreement lapses.

Which platform fits a hosting provider better?

OX App Suite is positioned for hosting providers, telcos and ISPs. Open-Xchange describes it as a white-label email, productivity and collaboration platform that can run on premises, in a public cloud or as the managed OX Cloud. Zimbra is sold as a product with Standard and Professional tiers and supports on-premises, private cloud or regional data center deployment, so it can serve a provider, but its white-label and multi-tenant fit should be confirmed for your model. Compare the branding options, tenant isolation, billing integration, and the operating model your support staff will run. Ask both vendors for references in your segment, and check how each handles upgrade windows and version support.

Can we run OX App Suite without a contract because of the AGPL mirrors?

The AGPL-3.0 mirrors let you read, build and modify the published code, but they do not by themselves give you a supported, licensed production service. The Open-Xchange Support Commitment defines release windows, and LTS releases are supported until the next LTS plus six months. Without a contract you would carry the testing, security patching and upgrades yourself, and you would not have a vendor commitment for fixes. Your legal team should confirm what the AGPL terms require when you distribute or host modified code, and whether any module falls under the separate license terms described in the Operations Guide. Ask Open-Xchange and any implementation partner to confirm the support scope in writing.

How DeployOpen supports the choice and the move

DeployOpen is a Chainscore Labs company that plans, implements, migrates, hardens and supports self-hosted platforms inside your own infrastructure, whether that is your cloud accounts, your data centers or an air-gapped network. For an Open-Xchange vs Zimbra decision, that means we can help you test both options against your own mailboxes, identity setup and hosting constraints before you commit. Most engagements run on a fixed scope, with deliverables and timelines agreed in writing before work starts, so the cost of evaluation, pilot and cutover is visible up front. We are not a vendor partner, reseller or certified provider of either Open-Xchange or Zimbra, and we do not favor either platform. Our job is to show you what each one would require in your environment and let the evidence set the direction.

The work that tends to decide this comparison is concrete: confirming the deployment model you need, checking whether an OX App Suite v8 Kubernetes footprint with Istio or ingress-nginx fits your platform team, and testing a Zimbra build path against your license and support position. A scoped assessment can also map your mailbox volume, calendar and contact data, and any Outlook or mobile sync dependencies, so that the migration plan is based on your own data. Ask any vendor, including us, to put the scope, the environments covered and the acceptance criteria in writing before you compare quotes.

Once a platform is live, ongoing support, upgrades and continuous testing can be handled under a retainer, which suits teams that do not want to rebuild in-house expertise for every release cycle. Retainers are priced from the agreed scope rather than from a published list, so ask for the covered services, response expectations and upgrade responsibilities in writing. Whichever platform you choose, confirm the support window of the release you deploy with the vendor, because that window, not the initial install, shapes your long-term operating effort.

How DeployOpen helps choose, implement or migrate

DeployOpen works in your own cloud accounts, data centers or air-gapped networks, so every card below starts from your environment rather than a generic install. The sequence runs from deciding whether OX App Suite or Zimbra fits your scenario, through architecture and identity review, fixed-scope build and migration, to evidence and ongoing support.

Scenario assessment first

Before any work, confirm whether you are a hosting provider, telco or ISP serving end customers, or an internal team that needs a groupware suite for staff. OX App Suite is positioned for service providers, while Zimbra's paid tiers are sold for on-premises, private cloud or regional data center deployments. Write down the user count, mailbox volume, Outlook and mobile needs, and the license terms you can accept, then compare the options against that list in writing.

Architecture and identity review

Map the target stack before choosing hardware. OX App Suite v8 is delivered as Helm charts and expects Kubernetes, Istio or a basic ingress-nginx option, Redis 7.4.x, and MariaDB with InnoDB. Zimbra 10.1 runs as a packaged server with its own components. Review how users will sign in, including OpenID Connect and SAML options, and confirm which of those your directory and identity provider support.

Fixed-scope implementation

Implementation is agreed as a written scope with deliverables and timelines before work starts. For this comparison, scope usually covers installation in your environment, storage design for attachments and files, backup and upgrade procedures, and the documentation your operators will use. Ask for the list of modules included, since Open-Xchange states that certain modules or features may be subject to custom packaging or separate fees set in the license agreement.

Migration planning and execution

Moving mailboxes, calendars, contacts and shared folders is the largest cost of switching between these suites. Plan the cutover in waves, define coexistence and rollback steps, and test a sample of accounts before production. Confirm which source and target formats your tools can read, and how client settings and mobile devices will be reconfigured. DeployOpen plans and executes these steps under the agreed scope.

Hardening and compliance evidence

After go-live, configure access controls, encryption at rest and in transit, logging, and patch procedures, then collect the configuration records and test results that your compliance assessor will ask for. DeployOpen prepares these systems and evidence. It does not issue audit reports, attestations or certifications, so confirm early which independent assessor your framework requires.

Ongoing retainers and upgrades

Ongoing support, upgrades and continuous testing are available as retainers. Check the vendor support windows before you commit: Open-Xchange supports a standard release for 12 weeks, and an LTS release until the next LTS plus six months. Zimbra 10.0 has reached end of general support, so confirm which Zimbra release your license covers and what patch cadence applies to it.

Open-Xchange vs Zimbra