The Dynamics GP 2013 are now out on Partnersource/Customersource, so you can start planning for the next version.
This is all *Subject to Change*, however, you shouldn't be expecting any major changes.
The following are no longer supported with Microsoft Dynamics GP 2013:
a. Windows XP all editions
b. Windows Server 2003 all editions
c. Internet Explorer 7.0
d. Microsoft Office 2007
e. Microsoft SQL Server 2005 all editions
f. Windows SharePoint Services 3.0
g. Microsoft Office SharePoint Server 2007
h. Office Communicator 2007
GP 2013 Launch Portal