Copy that crypt file from: com.whatsapp->Whatsapp->Databases.
Paste it into com.whatsapp->Whatsapp->Databases.
Install a fresh copy of Whatsapp, or just clear storage;
Put in your number and it's good to go.
My Experience this round...
OMG, it's been awhile since I need to transfer my long term Whatsapp number into another device.
Thought of trying that new feature that doesn't need to use the Cloud backup knowing that I've not deleted my images or videos or other media for almost pass 2 years, it has gathered around 20GB worth of storage.
Local backup it is then, halfway "preparing"; the receiving device said it was disconnected.
The Sending phone was still in "preparation" mode, but what's the point right? I guess it's zipping 20GB worth of data, might take a few more hours, so I cancelled it, and then all my chats were gone!
After a few hours of tinkering, I've found the backup file, that special Crypt file that is executed for backup each day at 2am.
At least I still have the one from the past few days instead of just removing the app entirely.
com.whatsapp->Whatsapp->Databases.
putting that file there and entering my number fresh again seems to do the trick and all my messages were back. Phew!
