Microsoft has announced that on October 14, support for Exchange Server 2016 and 2019 is ending, meaning no more security patches, bug fixes, or technical assistance once the deadline passes. If you’re still running on these versions, it’s no longer an option to delay moving everything to the cloud.
We understand there could be a number of reasons why you haven’t made the switch from Microsoft Exchange to Office 365, now Microsoft 365. However, those reasons may pale in comparison to the serious security risks your company will encounter if you delay the switch after your current versions are no longer supported.
We’re here to help you know what to do to prepare for this project.
Is It Time for You To Switch From Exchange to Microsoft 365?
For years, on‑premises Exchange servers offered control and familiarity. But the landscape has shifted. The good news is that this migration doesn’t have to be a reaction to a looming deadline — it can be a strategic decision.
Rather than simply replacing aging hardware and software tools, think about how email fits into your larger support for business objectives. Here are the key drivers:
- Modern collaboration and innovation: Exchange Online and Microsoft 365 integrate email with Teams, SharePoint, OneDrive, and emerging AI tools like Copilot, creating a unified platform for hybrid work.
- Security and compliance: Cloud services deliver continuous security updates, automated threat protection, and compliance features that help meet GDPR, HIPAA, and other regulatory requirements. Implementing Zero‑Trust principles becomes easier when identity and access controls are centralized in the cloud.
- Cost and resource optimization: Subscription licensing shifts spending from capital to operational expenses, eliminates server upgrades, and frees your IT staff to focus on strategic initiatives.
- Future‑proofing your environment: End‑of‑support dates apply not only to Exchange but also to related products like Office 2016/2019, Outlook 2016/2019, and Skype for Business. Moving to Microsoft 365 modernizes your entire productivity suite at once and aligns you with Microsoft’s long‑term roadmap.
For IT leaders, the question isn’t whether to migrate, but how to align the migration with your broader business objectives. A well‑planned migration can help your organization modernize collaboration, enhance security, and make better use of limited resources.
It is important to note that Microsoft is not leaving on-prem behind—Exchange Server Subscription Edition will continue for those who want it. But many organizations are shifting toward cloud-first strategies, bringing new workloads and services into the cloud for more flexibility.
Choosing a Migration Path: Cutover, Staged, or Hybrid?
Not every migration is the same. There are three approaches that get thrown around, and the right one depends on your environment and timeline:
- Cutover migration: A one‑time move for organizations with roughly 150 mailboxes or fewer, which migrates everything in one event. It’s simple and fast, but requires thorough preparation and user readiness.
- Staged migration: A staged migration is only designed for Exchange 2003 and Exchange 2007 environments, which have been out of support for many years.
- Hybrid migration: If you have more than 150 users to migrate or need to keep certain mailboxes on‑premises for compliance, latency, or phased rollout reasons, hybrid migration lets you maintain your on‑premises Exchange environment while moving batches of users to Exchange Online.
It may not be hard to choose. The process mainly depends on the version of Exchange you’re running and the number of users you need to migrate. Microsoft provides articles to help you determine the best option for your company. You can also work with experts who have helped navigate these migrations before to weigh the pros and cons of each approach based on your business needs and risk tolerance.
Ready, Set, Migrate: Preparing Your Environment
Once you’ve decided which method to use for the migration, it’s time to get ready. Migrating to Microsoft 365 is as much about cleaning house as it is about moving data. But don’t get tripped up assuming the technical steps will run themselves.
A smooth migration starts with a solid plan. Here are three things every IT leader should address before moving mailboxes.
- Sync your directory to the cloud. If you plan to run a hybrid environment or move users in stages, you’ll need to copy your on‑premises user accounts and passwords into Microsoft 365. Microsoft explains that directory synchronization is required for hybrid deployments because it keeps the same address book and sign‑in credentials in both places. Tools like Microsoft Entra Connect (formerly Azure AD Connect) handle this for you.
- Check app and device dependencies. Some business applications, phone systems, scanners, or printers may rely on Exchange for email delivery or authentication. Identify these systems early and verify whether they need updates or new connectors to work with Microsoft 365.
- Review your licensing. When you create or move mailboxes to Microsoft 365, you must assign each one a valid subscription. Evaluate which Microsoft 365 plans match your users’ needs and ensure you have enough licenses for everyone you plan to migrate.
By addressing these areas up front, you’ll make your Exchange to Microsoft 365 migration more predictable and reduce last‑minute surprises.
Use Communication, Training, and Governance To Make Your Microsoft 365 Migration Successful
Technology is only half the equation; your people will make the move successful. Here’s how to keep them on board:
- Communicate early and often. Tell your colleagues why you’re migrating and how it benefits them. Set expectations about what will change.
- Provide training. Offer quick‑start guides and workshops on Outlook Web, Teams, and SharePoint. Make sure people know how to access their email on Day 1.
- Plan your support team. Expect a surge of questions. Assign extra help‑desk staff or super‑users to respond quickly during the transition.
- Establish governance. Define who can create groups or SharePoint sites, set retention policies, and decide how sensitive data will be handled.
Engaging your people early will reduce resistance and ensure that the new tools will deliver its intended value.
Building Security Into Your Migration
As you prepare for migration, remember that moving email to the cloud reshapes security. You’re entrusting critical data to a new environment, so protection and compliance should be top of mind from day one.
With so much focus on data migration, it’s easy to overlook identity protections. Keep these steps in mind as you work on your Exchange-to-Microsoft 365 migration.
- Before migration: Turn on multifactor authentication (MFA) for all users and block legacy authentication protocols. Create dedicated admin accounts, protect them with MFA and just‑in‑time access, and set up SPF, DKIM, and DMARC to prevent spoofing.
- During migration: Monitor sign‑in and mail‑flow logs for unexpected legacy protocol use or misconfigurations. Consider testing conditional‑access policies and threat‑protection settings in a report‑only mode with pilot users before fully deploying and enforcing them across the organization.
- After cutover: Decommission old connectors and remove legacy relay paths. Tighten conditional‑access rules, retire unused admin privileges, and continue reviewing audit logs (which should automatically be on, but check and make sure).
Weaving these measures into your migration plan shows stakeholders that you’re not just moving mailboxes, you’re strengthening your organization’s security posture as you go.
You Don’t Have To Do This Alone
VLCM has guided organizations like yours through these migrations. We’ll help you choose the right strategy, prepare your environment, support your users, and secure your data, so you can focus on delivering value to your business.
Ready to begin? Let’s plan your Microsoft 365 migration together.
