You can convert .crypt12 WhatsApp backup files to the original .crypt file using WhatsApp Tri-Crypt / Omni-Crypt app, but you cannot convert it to any of the previously used version, including crypt9. Once you have the .crypt file, you can extract the messages with other tools.
This conversion entry was verified by us and conversion was flagged as wrong or not possible.
Usually this happens when the conversion would try to convert different types of data between each other, such as audio to image, or it is not possible because incompatibility between programs, caused by closed file formats, very limited support etc.
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