Only for voice .zip does it can (need to?) be .ogg; actually if you look at the codes, the API for audio seem to use .wav
The .wav format is always supported and unlikely to go away. The name of audio folder needs to be correctly only if you're using a skin that required it. If not, it is to be defaulted to be under data.zip\data\ui_nextgen\audio But can be override by any new UX's or directory created under installation location.
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