Microsoft Dynamics NAV 5.0 - Feature Enhancements Documents
This link wil bring you to a download of all 5.0 enhancements, catagorized per granule. It contains enhancement documents for version 3.70 to 5.0 and from 4.0 to 5.0 of Microsoft Dynamics NAV.
Good call ...
Since not everyone have access to partnersource, then I'll recommend you to just download it from the download section: