David Musgrave has some great Dex development advice in Quick Tip: Best Practice for Dexterity Version and Build Numbers
Quick Tip: Best Practice for Dexterity Version and Build Numbers – Developing for Dynamics GP – Site Home – MSDN Blogs
Tips & Hidden FeaturesDevelopment & Integration
Archived post from 2011. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.