Exchange Server Subscription Edition, usually called SE, is the version of Exchange for companies that keep mail on their own server. Exchange 2016 and 2019 reached the end of support on 14 October 2025. Exchange Server SE and AI belong in the same plan. If you are still planning the move, or have just finished it, the next question is how to bring AI to the same mailboxes.

Where Exchange SE fits

Many organisations keep Exchange on premises for good reasons: data stays on their own hardware, they control updates and they already have the skills. SE is the version Microsoft supports for them. If you run an older version, plan the move on its own schedule, and do not let AI projects wait for it.

The AI gap on premises

Built-in AI assistants are designed for mail in the vendor’s cloud. For an on-premises server, the staff who would benefit most are often left with nothing. People then fall back on pasting mail into chatbots, which is the pattern described in Shadow AI at work. The read-out is in AddSync AI vs Microsoft Copilot.

How AddSync AI reaches Exchange SE

AddSync reaches Exchange through EWS, with either the person’s own mailbox login or one global EWS user that has mailbox permissions. There is no impersonation. Mail stays where it is, and AddSync does not move it.

A checklist for the move and the AI

• Confirm which Exchange versions run today and when each will move to SE.
• Keep calendars in step during the move if some users are still on the old server.
• Decide the AI access path: global EWS user or personal login.
• Set data filters before the first question.
• Start with a pilot of five to ten people.

What stays the same

• Mail stays on your server. AddSync reaches it there and does not move it.
• The AI has four tools and cannot send, delete or move mail.
• Filters are global and the journal holds no mail text.
• The same rules apply later if some users move to Microsoft 365.

Questions for your migration partner

• Which servers move to SE, and in which order?
• How will calendars stay visible during the waves?
• What do you expect to be unavailable during the move?
• Who owns the AI decision, IT or the business?

Example: a four-step plan

1. Month 1Inventory servers, mailboxes and shared calendars.
2. Month 2Pilot the move with a small group and run an AI pilot on the old and new server.
3. Month 3Move in waves with calendar sync on.
4. Month 4Switch off the sync, keep the AI rules, review the journal.

Example, not a real customer. The timing depends on your size, so use it as a skeleton.

Calendars during the move

If you migrate in waves, calendars are the first thing people notice. AddSync Calendar keeps Exchange calendars, contacts and tasks in step with other systems, in the direction you choose. See Exchange Server sync.

Questions and answers

Does AddSync AI work with Exchange 2016 and 2019?

Yes. It works with Exchange Server 2016, 2019 and Subscription Edition.

Does mail leave my server?

The AI reads a message to answer a question and does not store it. AddSync reaches mail where it is and does not move it.

Do I need Microsoft 365 for AI?

No. AddSync AI works with on-premises Exchange, Microsoft 365, Gmail, Outlook.com and HCL Domino.

Who sets the rules?

IT does, once, with a guard, data filters and a journal.

Written by the AddSync team.