IceWarp to Office 365 Migration
IceWarp Server (self-hosted or cloud) → Microsoft 365. Mail over IMAP, calendars and contacts via CalDAV/CardDAV export, TeamChat wind-down plan. From $15/user, zero downtime cutover.
BitTitan Certified · Zero Data Loss Record · DNS Handled
Every mailbox. Every folder. Verified.
What staying actually costs.
IceWarp’s all-in-one pitch ends where Teams meetings, Intune device management, and Copilot begin. Standardizing on Microsoft means leaving.
IceWarp calendars/contacts live on CalDAV/CardDAV — no EWS. Fidelity depends on doing the export path right, which is exactly what we script.
Patch cycles, TLS renewals, storage growth — a mail server is a full-time tenant in your infrastructure. M365 evicts it.
Standard off-hours MX flip after delta sync — a 30-user IceWarp server completes within a week.
Everything handled. Nothing assumed.
Server-side IMAP mail sync
Mail and folder structure migrate over IMAP with delta passes, paced to your server’s capacity.
CalDAV/CardDAV export path
Calendars and contacts export via DAV/ICS/VCF server-side and import into Exchange Online — verified per user, recurring events checked.
GroupWare mapping
IceWarp shared folders and group calendars map to Microsoft 365 shared mailboxes and group calendars by agreed policy.
TeamChat wind-down
IceWarp TeamChat history can’t migrate to Teams — we plan the export/archive and the Teams rollout so collaboration doesn’t skip a beat.
DNS + deliverability
MX, SPF, DKIM, DMARC configured on Microsoft 365; the old server’s IP reputation stops being your problem.
Decommission runbook
After verification: mail routing off, DAV endpoints closed, server retired — documented so nothing keeps listening on port 25.
Assess. Plan. Migrate. Cutover.
Assess
1-2 days · Source audit, mailbox inventory, domain list. Fixed per-user quote in 24-48 hours.
Plan
1-2 days · Microsoft 365 tenant provisioned, domains verified, MFA + security baseline deployed.
Migrate
Background · Server-side pre-stage sync runs invisibly. Users keep working on the old system until cutover.
Cutover
2-4 hrs off-hours · MX/SPF/DKIM flip, final delta sync, Autodiscover repoint. 30 days hypercare.
The engineers on your project.
No outsourced ticket triage. The same three engineers handle source assessment, tenant provisioning, cutover night, and post-migration support on every IceWarp engagement.
Sreenivasa Reddy
Founder & Principal Migration Engineer
MCSE Messaging · 25 yrs · 500+ migrations led
Owns the discovery call and migration architecture: source assessment, licensing right-size, and the compliance/security mapping that decides which M365 SKU mix you actually need.
Roshan Pujari
Senior Migration Engineer · Source Systems Lead
Microsoft Certified · M365 Administrator
Runs source-side assessment and extraction: credentials, throttling strategy, batch design, and the pre-stage sync that makes cutover weekends boring.
Bhargav
Senior Migration Engineer · Mail Flow + Cutover
Microsoft Certified · Exchange + M365 Messaging
MX/SPF/DKIM/DMARC cutover and Autodiscover repoint. Owns the 2-4 hour cutover window plus post-cutover Outlook profile and mobile device resync.
The IceWarp-specific realities.
Generic migration guides skip these. They are the operational details that decide whether your cutover weekend is boring — which is the goal.
IceWarp has no EWS — calendars/contacts move via scripted CalDAV/CardDAV exports, not mailbox-protocol magic
TeamChat history cannot land in Teams — we archive it readably and plan the Teams rollout as part of cutover comms
Self-hosted IceWarp boxes are often undersized for bulk export — sync pacing keeps production mail flowing during migration
Frequently Asked Questions
Do IceWarp calendars and contacts migrate to Office 365?+
What happens to IceWarp TeamChat?+
How long does an IceWarp to Office 365 migration take?+
What is the downtime during a IceWarp to Microsoft 365 migration?+
Is there any risk of data loss?+
What does the migration include for $15/user?+
All-in-one, meet actually-all-in-one.
$15/user flat. Pre-staged sync, off-hours cutover, DNS handled, 30-day hypercare. Zero data loss record across 1.4M users.
Microsoft Solutions Partner · BitTitan certified · Fixed-fee · 500+ migrations
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Client overview A government services agency in Virginia, with over 1,000 employees, had been using a hosting panel-based IMAP system for their email and communication needs. As the agency grew, they faced challenges in managing email effectively, ensuring data security, and fostering collaboration across teams. Given the critical nature of their services, the agency needed a […]