<Tr> <Th> License </Th> <Td> Trialware </Td> </Tr> <Tr> <Th> Website </Th> <Td> products.office.com/exchange </Td> </Tr> <P> Microsoft Exchange Server is a mail server and calendaring server developed by Microsoft . It runs exclusively on Windows Server operating systems . </P> <P> The first version of Exchange Server to be published by Microsoft was Exchange Server 4.0 . Exchange initially used the X. 400 directory service but switched to Active Directory later . Versions 4.0 and 5.0 came bundled with an email client called Microsoft Exchange Client . It was discontinued in favor of Microsoft Outlook . </P>

What type of microsoft server serves as an email server