Hi Julia,
It would still be if that version is listed on the System Requirements page it is support. If it is not then that would not be a support OS. Here is a link of the supported OS's from the link I posted earlier:
Microsoft Windows Server 2008 R2 Standard Edition with or without SP 1
Microsoft Windows Server 2008 x64 Standard Edition with or without SP 2 (Microsoft Dynamics GP 10.0 SP 2 or later required)
Microsoft Windows Server 2008 Standard Edition with or without SP 2 (Microsoft Dynamics GP 10.0 SP 2 or later required)
Microsoft Windows Small Business Server 2008 Premium Edition with or without SP 2 (Microsoft Dynamics GP 10.0 SP 2 or later required)
Microsoft Windows Essential Business Server 2008 Premium Edition with or without SP 2(Microsoft Dynamics GP 10.0 SP 2 or later required)
Microsoft Windows Server 2003 x64 Standard Edition SP 2
Microsoft Windows Server 2003 R2 x64 Standard Edition SP 2
Microsoft Windows Server 2003 Standard Edition SP 2
Microsoft Windows Server 2003 R2 Standard Edition SP 2
Microsoft Windows Small Business Server 2003 Premium Edition SP 2
Microsoft Windows Small Business Server 2003 R2 Premium Edition SP 2
Microsoft Windows Small Business Server 2003 Standard Edition SP 2 (MSDE/SQL 2005 Express ONLY)
Microsoft Windows Small Business Server 2003 R2 Standard Edition SP 2 (MSDE/SQL 2005 Express ONLY
