We continue to get licensing clarification for GP 2013 in Top Tip: Limited User Rule Change and Business Portal Clarification
Top Tip: Limited User Rule Change and Business Portal Clarification – Inside Microsoft Dynamics GP – Site Home – MSDN Blogs
Install, Upgrade & AdminTips & Hidden FeaturesMicrosoft & the GP EcosystemGP 2013
Archived post from 2012. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.