Redmond channel partners reports that Dynamics GP 2013 SP2 Coming Later this Year . Expect more announcements during the Technical Airlift in September.
Dynamics GP 2013 SP2 Coming Later this Year — Redmond Channel Partner
Microsoft & the GP EcosystemGP 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.