[chef] What is the difference of using the -E flag on knife upload cookbook

[David Montgomery < >]

What is the difference of using the -E flag on knife upload cookbook

knife cookbook upload supervisor -E production
knife cookbook upload supervisor -E development
knife cookbook upload supervisor

Before I used to use knife cookbook upload supervisor -E development and it worked for production and development.  Now...some cookooks dont work in production now unless I upload using with the -E flag. 

Did opscode just make a change? 

This will cause me some issues to what it the proper method to use cookbooks that are environment neutral.  As of now....stuff is breaking

Thanks