It brings a lot of bug fixes and improvements upon GraniteDS 3.0 and some major improvements and new features:
Huge performance improvements on AMF serialization: GraniteDS is now 2 to 5 times faster than BlazeDS http://www.granitedataservices.com/2014/05/14/amf3-benchmark-graniteds-3-1-vs-blazeds-4-0/ Websocket JSR 356 specification support on both client and server. GraniteDS now supports websockets on Jetty 8/9 (server and client), Tomcat 7/8, TomEE, GlassFish 3/4, WildFly 8 and Tyrus (client).
Support for change sets with Hibernate 4.x (differential server to client updates)
Experimental support for clustered messaging with Hazelcast
Support for Weld 2.x (used in WildFly8 and GlassFish 4) and OpenWebBeans (used in TomEE) as CDI providers