Check Exchange current version

Get-ExchangeServer | fl Name,Edition,AdminDisplayVersion

Download new Exchange CU from Microsoft Web site.

Exchange Server build numbers and release dates | Microsoft Learn

Put Exchange in maintenance mode

Set-ServerComponentState "Exchange Hostname" -Component ServerWideOffline -State Inactive -Requester Maintenance

Verify Exchange maintenance mode status (it should show inactive for most component except two)

Get-ServerComponentState "Exchange Hostname” | Select Component, State

Reboot Exchange Server

Mount new ISO Exchange (example drive F:), then run below command as Administrator

F:\Setup.exe /Mode:Upgrade /IAcceptExchangeServerLicenseTerms_DiagnosticDataOFF

Verify new version after upgrade

Get-ExchangeServer | fl Name,Edition,AdminDisplayVersion

Reboot Exchange Server

Exit maintenance mode

Set-ServerComponentState “Exchange Hostname” –Component ServerWideOffline –State Active –Requester Maintenance

Set-ServerComponentState "Exchange Hostname" –Component HubTransport –State Active –Requester Maintenance

Verify all Exchange components active

Get-ServerComponentState "Exchange Hostname” | Select Component, State

Test send and receive email