For years, our company ran on self-hosted services and free office software. We used Postfix and Dovecot for email, SpamAssassin for filtering, LDAP for internal authentication, and Nextcloud with OnlyOffice for collaborative document editing. Mattermost handled chat, and Jitsi handled video meetings.
Some people had Excel or the full Microsoft Office suite, but Outlook was never part of the setup.
In 2026, we switched our MX records to Microsoft 365. The email migration is complete. We are still moving people off other services and working through a less visible part of the transition: changing who administers the environment.
I still value free software. What changed was my assessment of what our team could reasonably own for a business of roughly 150 users.
The cost was spread across two people
Our infrastructure team consists of two people. Email is one responsibility among systems administration, networking, DevOps, reliability work, and the other jobs that land with a small technical team.
Keeping mail flowing was only part of the work. We were also dealing with spam, malware, and phishing, while operating a public-facing mail service. That service created an ongoing responsibility for security, maintenance, and response.
Our existing Dovecot client setup also did not give us a workable way to require the MFA protection we wanted. That describes the environment we had deployed; it is not a claim that every self-hosted mail system has the same limitation.
Each of these problems might be manageable on its own. Together, they competed with every other responsibility the two of us carried. Supporting 150 people meant supporting their experience of email, including the problems that originated outside our own servers.
We kept running into the gaps between applications
We had tried many calendar solutions. The experience remained clunky, and nothing tied the whole environment together in the way we needed.
Nextcloud and OnlyOffice provided collaborative editing. Mattermost provided chat. Jitsi provided meetings. LDAP provided shared authentication for our internal and self-hosted applications. Those were useful capabilities, but having all the components did not give us a cohesive experience.
This mattered beyond administrator convenience. People needed calendars, documents, messages, and meetings to work together as part of an ordinary workday. Every gap became something to explain, support, or work around.
That need extended outside the company. We needed to accept meeting invitations from external partners and other organizations and collaborate with them. A setup that served only our internal workflows was not enough; working with people outside our environment was part of the requirement.
Consolidation changed more than email
Microsoft 365 gave us a place to bring those activities together. Teams replaced Mattermost, which we had been licensing, and also replaced Jitsi for video conferencing. The capabilities available to us in Teams made that consolidation an easy decision in our environment.
We are also moving from LDAP toward Entra for application identity. We want our web applications to fit a more modern approach to groups, roles, and permissions. That transition is still underway; the mail cutover should not be mistaken for completion of the entire identity and application migration.
The attraction was the combined environment. Evaluating email alone would have missed much of the reason for moving.
After the MX cutover
The most noticeable operational improvement has been spam and phishing handling. In our experience, coverage has been strong with very little hands-on intervention compared with the work we were doing before.
That is an observation from operating our environment, not a measured detection-rate comparison or a promise that filtering needs no oversight.
So far, I have not found a part of the everyday experience that is worse. The integrated collaboration tools have been a better fit for us, and the mail-security workload is substantially less demanding.
The mail cutover was a specific milestone: we changed the MX records so incoming mail would route to Microsoft 365. Email migration is now complete, while retirement of the remaining services continues. A successful cutover and a finished modernization program are different milestones.
The harder handoff is between teams
One challenge has been moving administration away from the Linux and systems administrators who previously owned these services and toward technical support.
Our support colleagues have mainly worked on Windows administration and office and desk issues. Taking responsibility for these systems expands the scope of their work. The transition has been bumpy, and getting comfortable with that level of administration takes time.
We are helping them through it. Moving to a managed platform changes the work; it does not make ownership, judgment, or training disappear.
For another small team considering this move, I would include that handoff in the project from the beginning. Decide what support should own, where escalation goes, and how people will gain experience with the new responsibilities. Those are recommendations from the transition, rather than a claim that we already have every part of that process settled.
What this changed about my thinking
I love free software, and I still see plenty of reasons to run it. But I also have to make decisions for the organization and the people supporting it.
For our business, the connective tissue of a full ecosystem was worth the move. We needed collaboration that worked across our own teams and with external partners, alongside a mail service whose ongoing demands fit the staffing we actually had.
We also needed the security capabilities and relief from operating the storage underneath those services. Email and collaboration data accumulate, and keeping backup copies takes significant disk space as well as administration. Moving mail and collaboration into Microsoft 365 meant our team no longer had to provision and maintain the underlying servers and storage for those workloads.
We still own decisions about access, retention, and recovery, including whether we need additional backups. But maintaining the infrastructure that stores and serves that data is a substantial responsibility to take off a two-person team.
The question I would now ask earlier is: can this team sustainably operate the whole experience, including security, integration, user support, and the work that happens when something goes wrong?
For our two-person infrastructure team and roughly 150 users, Microsoft 365 has been the better answer.
Account as of September 2026. Mail cutover in 2026. Based on the author's experience in one organization. The employer is intentionally unnamed.
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