The latest versions of WhatsApp's CRYPT format are heavily encrypted, so in order to work with the data inside you will first need to use tools that convert these files to its earliest format - CRYPT. In order to do that you will need to first convert CRYPT7 to CRYPT, before you can export any kind of data from them.
After that you can use programs and websites like Whatsapp Xtract or WhatCrypt tools to export the earlier chat backups from WhatsApp Messanger (.crypt files) and save them as in a HTML form which when viewed using a web browser will look exactly like your WhatsApp (CRYPT to HTML conversion).Open CRYPT7 file Open HTML file
An android forensic decoder
Online service for WhatsApp databases