Sony has post up there statement of what update 4.40 does for the Playstation 3.
About PlayStation®3 system software update version 4.40
PS3™ system software version 4.40 was released on March 21, 2013. Version 4.40 adds or updates the following features.
Main features in system software update version 4.40
[Closed Captions] has been added as a feature under (Video Settings).
The wireless stereo headset (CECHYA-0080 / CECHYA-0086) and the stereo headset (CECHYA-0088) now support PlayStation®2 Classics that have been downloaded from PlayStation®Store.
System software stability during use of some features has been improved.