Service Pack 1 for Microsoft Dynamics GP 2013 is now available! Do I really need to say more? Follow the link!
Service Pack 1 for Microsoft Dynamics GP 2013 is now available! – Dynamics GP Support and Services Blog
Microsoft & the GP EcosystemInstall, Upgrade & AdminGP 2013
Archived post from 2013. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.