Good app for merging two different Whatsapp backups
I've purchased the „Android WhatsApp Transfer“ app, because I had two different mobile phones and I already continued some Whatsapp conversations on the new one. The app worked very well for merging the two different backups. To do this, first plug your old phone to your computer, click on "backup messages", successively do the same with your new phone, then right click on one of the two new "local database", click on "export messages to crypt file", save it to a folder, then right click on the other "local database", click on "import Android Whatsapp backup data" (look for the exported crypt file you've saved in your folder) and after that, while having your new phone plugged to your computer, click on "transfer messages from database to Android"
By Chris J.