WhatApp Tri-Crypt app for Google Android phones can be used as a background process to convert even the old crypt8 as well as other previously used variants to the original legacy crypt format. After that, plenty of programs can be used to decrypt and extract the original crypt format, the most popular being program the Whatsapp Xtract.
Latest version is crypt12, so db.crypt8 to crypt conversion is more or less obsolete by now.