Different version WhatsApp's CRYPT format (for example .crypt7 files) are all heavily encrypted, which means that 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. Even though the file is found as msgstore.db.crypt7, only the .crypt7 is the actual file extension.
Once you have done this, you have to use utilities or 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 DB.CRYPT7 file Open HTML file
Online service for WhatsApp databases