Each version of this integration matches a specific build of Unreal Engine 4. Here is what has changed in the 2019.1.3.7048.1409 release of the integration (in addition to upgrading to the new Unreal build).

Unreal Engine 4.21/4.22 - Wwise 2019.1.3.7048.1409

• WG-43403 You're now prevented from adding an AkAudioEvent to a Niagara timeline using drag and drop.
• WG-43602 Removed log messages when SoundBanks contain no events.
• WG-44056 Because the only way to load a shared library on Magic Leap is through the mabu file, its implementation of getPluginDLLPath() is replaced by an error message that describes this.
• WG-44118 Fixed Load Bank and Unload Bank blueprint node that didn't resolve properly when using the string argument.
• WG-43178 Added preliminary support for Stadia.