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Case studies / Microsoft 365 Enterprise Migration

Microsoft 365 Enterprise
Migration.

Lotus Domino and Exchange to Exchange Online for a heritage manufacturer, with no downtime and no lost mail.

Microsoft 365Exchange OnlinePostfix
The glass façade of the Shard in London against a blue sky
Client
A UK heritage manufacturer
When
2024
Service
Microsoft Infrastructure
Led by
Huseyin Kartal, founder

The challenge

Mail lived on two systems at once: some users were on Lotus Domino, others on on-premises Exchange. The business wanted everyone on Exchange Online without a weekend of lost mail or a single risky cutover.

What we did

  1. Put a Postfix relay on an Ubuntu VM in the existing VMware estate as the single point every message arrived at. It stored no mailboxes; it only routed.
  2. Used a transport map so each user’s mail was delivered to wherever their mailbox lived that day: Domino, Exchange or Exchange Online.
  3. Moved users from Lotus to Exchange first, then in batches to Exchange Online, changing one line per user and reloading the relay.
  4. Kept distribution lists working across all three systems while their members were split between them.

Outcome

What changed

More work

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