Each version of this integration matches a specific build of Unreal Engine 4. Here is what has changed between the 2017.2.5.6619.962 and the 2017.2.6.6636.979 release of the integration (in addition to upgrading to the new Unreal build).

Unreal Engine 4.17/4.18/4.19 - Wwise 2017.2.6.6636.979

• WG-37921 Fixed hang on teardown.
• WG-38187 Fixed enabling/disabling of occlusion using the OcclusionRefreshInterval.
• WG-38282 Increased stack size to 1 MB on Switch platform.
• WG-38418 Fixed unload bank failed error when quitting game.