Each version of this integration matches a specific build of Unreal Engine 4. Here is what has changed between the 2017.1.5.6429.783 and the 2017.1.6.6446.801 release of the integration (in addition to upgrading to the new Unreal build).

Unreal Engine 4.15/4.16/4.17/4.18 - Wwise 2017.1.6.6446.801

• WG-35044 Made the behavior of overlapping reverb volumes sharing the same Auxiliary Bus more deterministic.
• WG-36446 Fixed: Crash when switching from map with SpatialAudioVolume to map without one.