Microsoft Dynamics GP 2015 – Functionality discontinuation notice. With the discontinuation of business portal, the availability and need for a runtime version of SharePoint is going away.
Collins Dynamics GP Blog: Microsoft Dynamics GP 2015 – Functionality discontinuation notice
Microsoft & the GP EcosystemGP 2015
Archived post from 2014. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.