Each version of this integration matches a specific build of Unreal Engine 4. Here is what has changed between the 2018.1.3.6784.1153 and the 2018.1.3.6784.1177 release of the integration (in addition to upgrading to the new Unreal build).

Unreal Engine 4.19/4.20/4.21 - Wwise 2018.1.3.6784.1177

• Added support for Unreal 4.21
• WG-38379: Added a new Wwise setting for the default Occlusion Collision Channel value used by Ak Component.
• WG-38497: Improved stability of the Sequencer while playing and moving around AkAudioEvent.
• WG-38746: Added setting to allow using Multi-core rendering.
• WG-39181: Fixed: Crash when resizing an AkAudioEvent section in the sequencer to its minimum width.
• WG-39408: Wwise Installation Path can now be configured per user. Use Wwise User Settings in the Project Settings to edit the Wwise installation path.
• WG-39669: Added parameter restrictions to Wall Occlusion in Ak Room component and Send Level in Ak Late Reverb Component.
• WG-39713: UAkAuxBus no longer causes premature initialization of FAkAudioDevice.
• WG-40128: Fixed: File handle leak in the IO hook.