All minimum system requirements are based on a single-user environment (one computer accessing a local database), and do not represent requirements for optimum performance of your Act! implementation. Customer registration and activation are required. Your system must meet the minimum requirements to be eligible for technical support.
Further information around Exchange support is available here.
Act! uses SQL Server® 2014 Express or your existing installation of SQL Server 2012 or newer. Note that SQL Server 2008 R2 is no longer a supported Microsoft product, and existing installations of this version must be upgraded for continued compatibility with Act!. Further information is available here. If you would like to use an edition of SQL Server other than the one provided, please consult Microsoft documentation for specific hardware and software requirements for that edition.