[Differences from 3.5 SP1] The following improvements were made to headers: WCF Data Services now correctly rejects an eTag header that has an unspecified value. WCF Data Services now returns an error and does not execute the request for a delete request to a link when an if-* header is in the request. WCF Data Services now returns an error to the client in the format (Atom, JSON) that the client specified in the Accept header. [Feature] 
Headers
B a t c h e d B i n a r y C o n t e n t
C h a n g e i n t e r c e p t o r s
E x c e p t i o n s
H e a d e r s
J S O N R e a d e r
M e r g e s
R e q u e s t s
S t r e a m s
U R I s