This blog applies to both Office 365 Enterprise and Microsoft 365 Enterprise

Exchange Server 2010 will reach end of support on October 13, 2020. Now is the time to start planning your migration from Exchange 2010 to Office 365 or Exchange 2016. We have outlined the options below.

End of support – What does this mean to my business?

Exchange Server has a support lifecycle during which we provide new features, bug fixes, security fixes, and so on. This lifecycle typically lasts for 10 years from the date of the product’s initial release, and the end of this lifecycle is known as the product’s end of support. When Exchange 2010 reaches its end of support on October 13, 2020, Microsoft will no longer provide:

  • Technical support for problems that may occur;
  • Bug fixes for issues that are discovered and that may impact the stability and usability of the server;
  • Security fixes for vulnerabilities that are discovered and that may make the server vulnerable to security breaches;
  • Time zone updates.

Your installation of Exchange 2010 will continue to run after this date. However, because of the changes listed above, we strongly recommend that you migrate from Exchange 2010 as soon as possible.

Options

With Exchange 2010 reaching its end of support, this is a great time to explore your options and prepare a migration plan. You can:

  • Migrate fully to Office 365. Migrate mailboxes using cutover, minimal hybrid, or full hybrid migration, then remove on-premises Exchange servers and Active Directory.
  • Migrate your Exchange 2010 servers to Exchange 2016 on your on-premises servers.

Important
If your organization chooses to migrate mailboxes to Office 365 but intends to keep DirSync or Azure AD Connect in place to continue managing user accounts from on-premises Active Directory, you need to keep at least one Exchange server on-premises. If the last Exchange server is removed, you won’t be able to make changes to Exchange recipients in Exchange Online. This is because the source of authority remains in your on-premises Active Directory and changes need to be made there. In this scenario, you have the following options:

  • (Recommended) If you can migrate your mailboxes to Office 365 and upgrade your servers by October 13, 2020, use Exchange 2010 to connect to Office 365 and migrate mailboxes. Next, migrate Exchange 2010 to Exchange 2016 and decommission any remaining Exchange 2010 servers.
  • If you can’t complete the mailbox migration and on-premises server upgrade by October 13, 2020, upgrade your on-premises Exchange 2010 servers to Exchange 2016 first, then use Exchange 2016 to connect to Office 365 and migrate mailboxes.

While a little more complicated, you may also migrate mailboxes to Office 365 while migrating your on-premises Exchange 2010 servers to Exchange 2016.

Here are the three paths you can take to avoid the end of support for Exchange Server 2010.

Exchange Server 2010

Migrating to Office 365

Migrating your email to Office 365 is your best and simplest option to help you retire your Exchange 2010 deployment. With a migration to Office 365, you can make a single hop from old technology to state-of-the-art features:

  • Compliance capabilities such as Retention Policies, In-Place and Litigation Hold, in-place eDiscovery, and more;
  • Microsoft Teams;
  • Power BI;
  • Focused Inbox;
  • Delve Analytics;

Office 365 also gets new features and experiences first and you and your users can usually start using them right away. In addition to new features, you won’t have to worry about:

  • Purchasing and maintaining hardware;
  • Paying for heating and cooling of your servers;
  • Keeping up to date on security, product, and time zone fixes;
  • Maintaining storage and software to support compliance requirements;
  • Upgrading to a new version of Exchange – you’re always on the latest version of Exchange in Office 365.

How should I migrate to Office 365?

Depending on your organization, you have a few options that’ll help you get to Office 365. When choosing a migration option, you need to consider a few things like the number of seats or mailboxes you need to move, how long you want the migration to last, and whether you need a seamless integration between your on-premises installation and Office 365 during the migration. This table shows your migration options and the most important factors that’ll determine which method you’ll use.

 

Migration option

Organization size

Duration

Cutover migration

Fewer than 150 seats

A week or less

Minimal hybrid migration

Fewer than 150 seats

A few weeks or less

Full hybrid migration

More than 150 seats

A few weeks or more

Cutover migration

A cutover migration is one where, at a pre-selected date and time, you’ll migrate all your mailboxes, distribution groups, contacts, and so on, to Office 365; when you’ve finished, you’ll shut down your on-premises Exchange servers and start using Office 365 exclusively.

The cutover migration method is great for small organizations that don’t have very many mailboxes, want to get to Office 365 quickly, and don’t want to deal with some of the complexities of the other methods. But it’s also somewhat limited because it should be completed in a week or less and because it requires users to reconfigure their Outlook profiles. While cutover migration can handle up to 2,000 mailboxes, we strongly recommend you migrate a maximum of 150 mailboxes with this method. If you try to migrate more than 150 mailboxes, you could run out of time to transfer all the mailboxes before your deadline, and your IT support staff may get overwhelmed helping users reconfigure Outlook.

If you’re thinking about doing a cutover migration, here are a few things to think consider:

  • Office 365 will need to connect to your Exchange 2010 servers using Outlook Anywhere over TCP port 443;
  • All on-premises mailboxes will be moved to Office 365;
  • You’ll need an on-premises administrator account that has access to read the contents of your users’ mailboxes;
  • The Exchange 2010 accepted domains that you want to use in Office 365 need to be added as verified domains in the service;
  •  Between the time you start the migration and when you begin the completion phase, Office 365 will periodically synchronize the Office 365 and on-premises mailboxes. This lets you complete the migration without worrying about email being left behind in your on-premises mailboxes;
  • Users will receive new temporary passwords for their Office 365 account that they’ll need to change when they log in to their mailboxes for the first time;
  • You’ll need an Office 365 license that includes Exchange Online for each user mailbox you migrate;
  • Users will need to set up a new Outlook profile on each of their devices and download their email again. The amount of email that Outlook will download can vary.

Minimal hybrid migration

A minimal hybrid, or express, migration is one where you have a few hundred mailboxes that you want to migrate to Office 365, can complete the migration within a few weeks, and don’t need any of the advanced hybrid migration features like shared Free/Busy calendar information.

Minimal hybrid migration is great for organizations that need to take more time to migrate their mailboxes to Office 365, but still plan to complete the migration within a few weeks. You get some benefits of the more advanced full hybrid migration without many of the complexities. You can control how many, and which, mailboxes are migrated at a given time; Office 365 mailboxes will be created with the username and passwords of their on-premises accounts; and, unlike cutover migrations, your users won’t need to recreate their Outlook profiles.

If you’re thinking about doing minimal hybrid migration, here are a few things to consider:

  • You’ll need to perform a one-time directory synchronization between your on-premises Active Directory servers and Office 365;
  • Users will be able to log in to their Office 365 mailbox using the same username and password they were using when their mailbox was migrated;
  • You’ll need an Office 365 license that includes Exchange Online for each user mailbox you migrate;
  • Users don’t need to set up a new Outlook profile on most of their devices (some older Android phones might need a new profile) and won’t need to re-download their email.

To learn more about minimal hybrid migration, take a look at Use Minimal Hybrid to quickly migrate Exchange mailboxes to Office 365

Full hybrid

A full hybrid migration is one where your organization has many hundreds, up to tens of thousands, of mailboxes and you want to move some or all of them to Office 365. Because these migrations are typically longer-term, hybrid migrations make it possible to:

  • Show on-premises users the free/busy calendar information for users in Office 365, and vice versa;
  • See a unified global address list that contains recipients in both on-premises and Office 365;
  • View full Outlook recipient cards for all users, regardless of whether they’re on-premises or in Office 365;
  • Secure email communication between on-premises Exchange servers and Office 365 using TLS and certificates;
  • Treat messages sent between on-premises Exchange servers and Office 365 as internal, enabling them to:
  • Be properly evaluated and processed by transport and compliance agents targeting internal messages;
  • Bypass anti-spam filters.

Full hybrid migrations are best for organizations that expect to stay in a hybrid configuration for many months or more. You’ll get the features listed earlier in this section, plus directory synchronization, better integrated compliance features, and the ability to move mailboxes to and from Office 365 using online mailbox moves. Office 365 becomes an extension of your on-premises organization.

If you’re thinking about doing a full hybrid migration, here are a few things to consider:

Full hybrid migrations aren’t suited to all types of organizations. Due to the complexity of full hybrid migrations, organizations with less than a few hundred mailboxes don’t typically see benefits that justify the effort and cost needed to set one up. If this sounds like your organization, we strongly recommend that you consider Cutover or Minimal hybrid migrations instead;

  • You’ll need to set up directory synchronization using Azure Active Directory Connect (AADConnect) between your on-premises Active Directory servers and Office 365;
  • Users will be able to log in to their Office 365 mailbox using the same username and password they use when they log into the local network (requires Azure Active Directory Connect with password synchronization and/or Active Directory Federation Services);
  • You’ll need an Office 365 license that includes Exchange Online for each user mailbox you migrate;
  • Users don’t need to set up a new Outlook profile on most of their devices (some older Android phones might need a new profile) and won’t need to re-download their email.


Important

If your organization chooses to migrate mailboxes to Office 365 but intends to keep DirSync or Azure AD Connect in place to continue managing user accounts from on-premises Active Directory, you need to keep at least one Exchange server on-premises. If the last Exchange server is removed, you won’t be able to make changes to Exchange recipients in Exchange Online. This is because the source of authority remains in your on-premises Active Directory and changes need to be made there.

If a full hybrid migration sounds right for you, take a look at the following resources to help you with your migration:

Need help?

MessageOps can assist you with your migration to Office 365. We have migrated over 6 Million users to the Microsoft cloud and are ready to support your unique requirements. Contact us today! https://messageops.com/services/professional-services/