If your clients have been asking you when support for their version of GP will be discontinued, please see below GP 8.0 Support will be discontinued on 10/13/2009
https://mbs.microsoft.com/customersource/support/information/supportinformation/gp80_standard_ends_oct09.htm?printpage=false&stext=Great%20Plains%208.0%20support
GP 9.0 Support will be discontinued on 1/11/2011
http://support.microsoft.com/lifecycle/?p1=10479
Note – for those clients interested in moving their DBs to a new server – right now it does not look like GP 9.0 will be compatible with Windows 7 or Server 2008 R2
GP 10.0 Support will be discontinued on 10/09/2012
http://support.microsoft.com/lifecycle/?p1=12629