SmartMail will run on any version of Windows from 3.1x, thru Windows 95 to Window NT4. OS/2 Warp is also supported. It requires a minimum of 4Mb of free memory, 640 x 480 resolution screen and at least 10 MB of free disk space. Better specification machines are of course recommended. For best performance, use 800 x 600 resolution or better, with 256 colors, and a 486/66 processor or better.