Microsoft has announced a preview build of Exchange Server 2019 is now available. You can download it here.
Here are some of the key features in each of these areas:
Security: Exchange Server 2019 installed on Windows Server 2019 Core provides the most secure platform for Exchange. You also have the option of installing the Exchange 2019 Preview onto Windows Server 2016 Core or Windows Server 2016/2019 with Desktop Experience, but we have worked hard to make sure running Exchange on Windows Server Core 2019 is the best choice for our code.
Performance: Exchange Server to take advantage of the larger core and memory packed systems our customers buy these days. We’re confident you can be very successful running Exchange Server with up to 48 processor cores and 256GB of RAM.
Exchange 2019 will support tiering of storage using SSD’s at release time, but that is currently not enabled for the Public Preview release. SSD’s are going to be used to store (read/write) hot data in a sort of intelligent cache, lowering overall latency and in the end benefitting user experience.
The new Calendar Sharing model from Office 365 will be ported to Exchange on-premises. More information on this feature in Exchange Online here.
Courtesy :- https://blogs.technet.microsoft.com/exchange/2018/07/24/exchange-server-2019-public-preview/