Now Available: Business Portal 6.1 for Microsoft Dynamics GP 2013 This may be last release of BP. Microsoft is expected to drop Business Portal with GP 2015, Due at the end of this calendar year. BP features or equivalents will present in the web client and related apps.
Now Available: Business Portal 6.1 for Microsoft Dynamics GP 2013 – Dynamics GP Support and Services Blog – Microsoft Dynamics GP – Microsoft Dynamics Community
Microsoft & the GP EcosystemGP 2015GP 2013
Archived post from 2014. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.