License Type: Online Activation
Online Activation Keys are only binding to your Operating System, so it's advisable to do image backup of your Operating System after activation, in case your OS crashes in the future
it is recommended to install Exchange Server 2019 onto Windows Server 2019 Server Core. Exchange Server 2019 installed on Windows Server 2019 Core provides the most secure platform for Exchange. You also have the option of installing Exchange 2019 onto Windows Server 2019 with Desktop Experience.
Overview of Microsoft Exchange Server Features
The ability to use "up to 48 processor cores and 256GB of RAM."
Support for solid-state drives, enabling improved e-mail search.
A Dynamic Database Cache feature that provides "more memory to active database copies."
International e-mail (EAI/IDN) routing support.