Each version of this integration matches a specific build of Unreal Engine 4. Here is what has changed in the Unreal Engine October 2013 release of the integration (in addition to upgrading to the new Unreal build).

October 2013 - Wwise v2013.2.1

• Added bank generation for PlayStation4 and Xbox One.
• Added AkReverbVolume, allowing for mapping a volume in space to a Wwise auxiliary bus.
• UI-128 Fixed: Implemented asynchronous IO access.