I recently ran into this issue when trying to start an upgrade from GP 2010 to GP 2013.  Here is the scenario:

There is no better time to buy Microsoft Dynamics GP. Make sure you take advantage of the below prior to October 1, 2012!

As part of the Microsoft Dynamics GP 2013 launch, Microsoft announced a new pricing model called Perpetual.

The License Migration Transition Upgrade (LMTU) applies to all customers who acquire their active Microsoft Dynamics GP solution before October 1, 2012, and are current on their enhancement plan, irrespective of when you choose to execute the upgrade*.

Favorable Upgrade Rules

ParaGrafix Integration - ParaGrafix Integration for Microsoft Dynamics GP
allows companies to smoothly integrate with Quantara

ParaGrafix Integration for Microsoft Dynamics GP
allows companies to smoothly integrate with Quantara
Software's ParaGrafix, a third-party sales configurator.
ParaGrafix will enable your company to use a rules

• Business Intelligence capabilities help people at all levels of your organization transform data into actionable insight. Microsoft Dynamics GP offers a wide range of reporting and analysis tools to help equip your people to effectively monitor, analyze, and plan.
   
• Business Productivity is increased by a solution that works the way your people do. Microsoft Dynamics GP delivers the right tools to enable your organization and all of the people in it to tackle the most complex business challenges.

Microsoft Dynamics GP Overview