Last week, ESRI released v1.4 of their JavaScript API. A full list of what is new can be found here.

In addition to bug fixes, v1.4 has the following improvements:

• Support for Virtual Earth (Bing) maps and geocoding (VE authentication tokens are required)
• Support for ArcGIS Server network analysis services for route finding
• Render support for symbols based on data attributes 
• Multiple graphics layers
• Support for Dojo 1.3.1
• Improved vector render performance in Internet Explorer