Convert CRYPT12 to CRYPT

Converting newer WhatsApp Encrypted Database Files (v12) to the original .crypt file relates to users attempting to recover their WhatsApp backup files.

Your only option, most likely, is using Omni-Crypt, an Android app used to decrypt and convert CRYPT databases. To do so, you will, however, need Root Access to your device, which might jeopardize your warranty agreement.

Nowadays, most Android devices run on Android 4.0 (or higher), and you no longer need Root Access when using Omni-Crypt for .crypt12 to .crypt conversions.