Microsoft plans to release a new web client for Microsoft Dynamics GP in 2016 to replace the Silverlight web client.
From MSDW, The Microsoft Dynamics GP Web Client Prepares to Shed its Skin in 2016
The Microsoft Dynamics GP Web Client Prepares to Shed its Skin in 2016 – MSDynamicsWorld.com
Archived post from 2015. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.