- How to merge a What'sApp back up from old phone to same What
- How to recover facebook password without email and phone number - Guide
- How to delete whatsapp account without phone - Guide
- Samsung default password for phone lock - Guide
- Facebook account hacked email and phone changed ✓ - Facebook Forum
- How to import contacts from sim to phone - Guide
There's no official way to merge two WhatsApp backups together. However, I found a method on XDA forum that may work to merge backups, but it will require some technical knowledges. I recommend you creating a copy of your backups before.
Alternatively, you can export your old chats manually to keep a copy of them in a text file. Open a chat, select the picture of your contact and select Export Chat > Attach Media > Mail. The 10,000 latest messages will be included - 40,000 messages if you don't attach the media.