When you place your old .crypt backups from Whatsapp to the default folder of latest WhatApp Messenger app for Android, the program will automatically convert it to the latest variant possible, which atm is crypt12 files. This means you cannot create crypt12 files anymore and crypt to crypt10 conversion is not possible.
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.
If you find entry that you feel is flagged as bad wrongly, please tell us in the discussion below with as much as information as possible so we can fix it.