If you want to restore a less recent backup, rename the backup file you wish to restore from msgstore-YYYY-MM-DD.1.db.crypt12 to msgstore.db.crypt12 before reinstalling WhatsApp. Also, make sure you rename or delete the original msgstore.db.crypt12 file.
You can delete DB.CRYPT12 files to reclaim storage space but you will delete messages stored in the DB.CRYPT12 database. Common DB.CRYPT12 Filenames. msgstore.db.crypt12 - The name of the common database file used by WhatsApp Messenger that is stored in your device storage. Programs that open DB.CRYPT12 files. Sort. Windows. WhatsApp Viewer. Free.