Microsoft Exchange Server 2019 CU3 X64 MSDN Free Download
To get the latest version of Exchange 2019, download and install Cumulative Update 12 for Exchange Server 2019. Each CU is a full installation of Exchange that includes all updates and changes from previous CUs. When installing a new Exchange server using the latest released CU, you don't need to install Exchange RTM or any previously released CU.
Microsoft Exchange Server 2019 CU3 x64 MSDN Free Download