This is a perpetual licence for on-premises deployment of Exchange Server 2019, now available to purchase on CSP.
Exchange Server 2019 requires Windows Server 2019. Exchange Server 2019 installed on Windows Server 2019 Core provides the most secure platform for Exchange as it has a smaller footprint with a greatly reduced attack surface and less features not critical for the mail server. This boost both security and performance.
Exchange Server 2019 now uses Server Garbage Collection (GC) making it better at handling a larger number of jobs, dealing with more requests per second and handles processing power more efficiently.
Exchange Server 2019 uses SSD (solid-state driver) and JBOD (just a bunch of disks) together to decrease latency by up to 50%.
To discover the full list of improvements made to Exchange Server 2019, watch the Microsoft Ignite announcement.