Exchange 2019

Microsoft released a new version of Exchange Server in 2019. It brings in some new features to the mail and calendar server, including improvements when it comes to security and performance. To help you discern whether or not the new version is right for you, we have summarized the most important new innovations.

Key Exchange 2019 features

Many changes to Exchange Server 2019 have happened behind the scenes and therefore are not directly tangible to users. On the other hand, other changes directly affect the workflow of employees whose companies rely on Microsoft Exchange Server 2019. Some features have become interesting again, particularly to administrators.

Meta Cache Database (MCDB)

If you have your own (physical) server and equip it with SSD drives, you can use the Meta Cache Database (MCDB) on Exchange 2019. MCDB is already used in Microsoft 365. With this method, meta information is stored around the mailbox (for example, the folder structure). This accelerates access and search and gives administrators the option of accommodating more users in one server instance. This in turn, can reduce costs.

Dynamic Database Cache (DDC)

Dynamic Database Cache (DDC) also makes the Exchange Server faster. Administrators specify how much storage space a database can occupy on an Exchange Server. However, the number of active database changes resulted in poor utilization because available storage remains unused. In Exchange 2019, DDC allows the allocated storage capacity to dynamically adapt to the situation.

Search index

Microsoft has completely rebuilt the search index in Exchange 2019. In earlier versions, the index was separated from the mailbox database. This is no longer necessary in the new version of Exchange Server. The search index is now located directly in the mailbox database. This makes the administration much less complicated and also increases the speed of the search.

Windows Server Core

Microsoft offers Window Server Core administrators minimal server system execution. In the past, however, this could not be used in combination with an Exchange Server. Exchange 2019 now provides this option. Since Server Core is much simpler than the standard version, it saves a lot of configuration work and eliminates unnecessary services that only consume resources. In addition to saving time, Windows Server Core also promises more security: The simple structure gives criminals fewer points of attack and administrators can build in fewer (security-relevant) errors.


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Calendar extensions

Exchange 2019 also provides the end user with new functions, all related to the calendar. With the “Do Not Forward” function, users who have created a meeting specify that invited users are not allowed to forward this invitation. This allows the creator of the event to retain control over who is part of the meeting. In addition, Exchange Server 2019 gives users more options to create an Out of Office message: If you are not in the office for a certain period of time, you can block your calendar for that period. This includes automatically rejecting meeting requests for this period.

Another new feature in the context of the calendar is aimed primarily at admins: They now have a completely new cmdlet and an extended cmdlet (“command-let”) available. The newly introduced command allows administrators to delete events (such as meetings) from the calendar. In the past, the problem was that events created by employees who were no longer with the company would continue to exist forever on other people’s calendars. Admins can now use Remove-CalendarEvents to delete entries in the calendar again. An extension has been added to the Add-FollowerPermissions cmdlet: PowerShell now allows administrators to assign alternate permissions.

E-Mail Address Internationalization (EAI)

Something else interesting for end users: Email Address Internationalization (EAI) ensures fewer problems when sending emails in a global context. International email users are no longer restricted to the limited ASCII code (based on the English alphabet). Instead, the extended UTF-8 can be used. To achieve this, the address had to be converted in earlier versions of Exchange. This is no longer necessary. In Exchange 2019, EAI allows email addresses with international characters to be used.

Remote functions in Exchange 2019: Unified Messaging

For some companies, this is not an important problem: As of Exchange Server 2019, Microsoft will no longer continue their Unified Messaging (UM) service. In previous versions, the server offered extensive voice mail functions. If you don’t want to miss out on these features in the future, you will have to switch to another service. Microsoft itself is dropping UM in favor of Skype for Business, which has a similar range of functions. Cloud voicemail, which can then be accessed with Skype for Business, is an integral part of Microsoft 365, Microsoft’s SaaS solution. Accordingly, companies are to switch to the cloud service.


If you want to continue using Unified Messaging, you should stick with the 2016 version of Exchange. Microsoft still offers extended support until October 2025.

More Microsoft enhancements to Exchange 2019

In addition to the obvious new features, Microsoft has introduced some background improvements in Exchange Server 2019. These are primarily security and performance enhancements. For more protection against attackers, Microsoft primarily provides the above-mentioned option of using Exchange in combination with Windows Server Core. At the same time, however, the new version relies on stricter rules: With the move to Exchange 2019, only the TLS protocol from version 1.2 will still be supported. All earlier versions are no longer secure and are therefore no longer supported by Exchange - Microsoft is forcing administrators to be more secure.

In addition, the new Exchange version provides administrators with more ways to limit access to the configuration area (Admin Center & Powershell) of the servers with the Client Access Rules. This also provides more security: For example, admins can now only allow certain IP addresses and can therefore block access from outside directly using the server without having the rely on an additional firewall.

Even more has happened with the performance of the new Exchange Server. The major innovations in the form of MCDB, DDC and the change in the search index have also been highlighted above. However, Exchange Server 2019 contains even more improvements: By switching from Workstation Garbage Collection (GC) to Server GC, available performance can be better integrated. Server GC handles more requests per second than the workstation version. However, this only brings a boost in efficiency if multiple processor cores are used. This is why up to 48 processor cores can be used in parallel in Exchange 2019.

Since the changes in Exchange 2019 also focus on improving memory, Microsoft has provided better support for modern hardware in this context. In addition to the usual HDDs, you can now also use SSD memory in your Exchange Server – together with the traditional hard disks. A total of 256 GB of RAM is now available.


Microsoft assumes that its changes can reduce latency by half. In addition, 20 percent more users can be accommodated per server in this way. Conversely, this means that fewer servers have to be used in parallel – which should lead to cost savings.

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Requirements for Exchange 2019

With the new version of Exchange, there are also new requirements for the server environment. The Exchange 2019 hardware requirements are particularly important here so that the new version can be used effortlessly:

  • Processor: 64-bit processors from Intel or AMD
  • Memory: 128 GB for installation, 200 MB free space on the system drive and 500 MB free space on the Message Queue Database drive.
  • Hard disk space: 20 GB for installation, 200 MB free space on the system drive and 500 MB free space on the Message Queue Database drive.

The information published by Microsoft regarding the minimum memory requirements has caused particular uncertainty among administrators, as they are comparatively high. In fact, the manufacturer states that you should have at least 128 GB of memory for best performance. However, it is still possible to implement Exchange 2019 even with smaller memory volumes.

Also interesting: The required software. To use Exchange 2019, you also need Windows Server 2019. This will mean upgrading here too for most companies, since the administration tools are also designed for Windows 10. As .NET framework Exchange 2019 requires version 4.7.2. Users can access the Exchange Server with Outlook from version 2013.


To upgrade the system to Exchange Server 2019, you will need to have already been using versions 2013 or 2016. If you’re still using Exchange 2010, you’ll first have to upgrade to Exchange 2013.

It is possible to combine the new version with the 2016 or 2013 versions in order not to switch completely to the new system immediately. Another combination is also possible: Exchange can be used in hybrid operation with Microsoft 365. As can already be seen from the elimination of Unified Exchange, Microsoft is trying to persuade companies to switch to the cloud service Microsoft 365 and is offering an easy entry into the system with this hybrid construction. Microsoft provides special software for this, which enables the on-site exchange of the installation with the cloud solution.

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