Share via

What to do? SE or Decommission

vas90 0 Reputation points
2025-11-29T00:17:03.9066667+00:00

I’ll start by outlining our current environment for context:

Two standalone Exchange Server 2016 VMs. Primarily used for recipient management in a hybrid setup. Also functions as an anonymous relay for two LOB applications — one of which requires the mail service to reside on the same network as the application (as per vendor requirement). We have not opted for Extended Support (ESU) and installed the latest available Security Update last week.

Management has been presented with the following options to move forward:

  1. Perform a legacy upgrade — build two new servers and migrate from Exchange 2016 to Subscription Edition (SE).
  2. Migrate LOB applications to another SMTP service — this would allow continued use of Exchange Management Shell for recipient management (by setting up a new server, preparing the schema for SE, and following Microsoft’s decommissioning process).
  3. Migrate both LOB applications to another SMTP service and management to alternative platforms such as Easy365 or ManageEngine, removing the dependency on Exchange entirely.
  4. Cloud management, however, we still need the use of synchronising device objects, so may not be an actual option.

This post is mainly to gather some insights and general discussion around the best path forward.

From a risk management perspective, since we’re effectively sitting on a time bomb without further Microsoft updates, I’m leaning toward option 2, especially given that all mailboxes have long been migrated to Exchange Online.

What should I be watching out for with this approach? It seems many have taken a similar path — I’d appreciate hearing about any challenges or pitfalls you encountered and how you mitigated them during implementation.

Exchange | Hybrid management
Exchange | Hybrid management
The administration of a hybrid deployment that connects on-premises Exchange Server with Exchange Online, enabling seamless integration and centralized control.
0 comments

1 answer

Sort by: Most helpful
Most helpful Newest Oldest
  1. Jade-T 8,530 Reputation points Microsoft External Staff Moderator
    2025-11-29T12:17:18.5966667+00:00

    Hi @vas90

    Thank you for posting your question in the Q&A Forum and sharing the details of your environment and the options you’re currently evaluating.

    With Exchange Server 2016 now past its support lifecycle, many hybrid environments are exploring similar next steps, so your question is certainly understandable.

    Since you’re considering Option 2, the points below summarize observations that are commonly raised in similar community discussions. These are general themes based on recurring patterns and publicly available Microsoft documentation, so the relevance may vary depending on your specific setup.

    1. SMTP Relay Considerations
    A frequent topic in related threads is how to handle legacy LOB applications that rely on the Exchange 2016 server for relay. Some organizations have moved the relay workload to another supported SMTP service or deployed a lightweight relay on the required network segment, depending on what their vendor supports.

    One point often highlighted is verifying what the vendor means by the requirement for the service to be “on the same network”, as clarifying this early can help avoid design changes later.

    2. Recipient Management & SE Deployment
    For those deploying a minimal Exchange Subscription Edition (SE) server strictly for recipient management, a few common considerations are mentioned:

    • There is an ongoing maintenance commitment (updates, patching, operational overhead).
    • Some teams compare this long-term requirement with third-party management tools before deciding.

    These tend to be strategic factors reported by users rather than strict technical limitations.

    3. Decommissioning the Exchange 2016 Servers
    In similar discussions, one of the more common pitfalls relates to the decommissioning process. Users frequently point out the importance of following Microsoft’s documented uninstall steps rather than shutting down or deleting the VMs directly, since Exchange stores configuration in Active Directory.

    Referring to the official process is often mentioned as a way to help avoid attribute-related issues later on.

    Note: Because schema preparation and hybrid recipient management involve core directory components, some organizations choose to involve a Microsoft partner or specialist for the final steps. This is just a general observation from community feedback, not a requirement.

    For further details, you may find the following Microsoft resources helpful:

    I hope this information helps provide some context for the discussion. If you have any questions or need clarification, feel free to reach out.

    If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".    

    Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread. 

Your answer

Answers can be marked as 'Accepted' by the question author and 'Recommended' by moderators, which helps users know the answer solved the author's problem.