Originally Posted by Simone98RC
Exactly, but you'll lost newer messages, as I said you can't merge ones with older
Sorry if this is too late for the reply. I just joined the forum.
I had this same problem. As rightly mentioned is an earlier post, you just need to copy paste the old folder and restore from that. Your problem of new messages lost will happen if there is a significant time difference between back up and restore. If not I don't think the new messages are lost.
In my case I had backed up whatsapp but was using it on another handset till the time I restored and so lost the new ones (or had the option to restore only one of the two). I havent come across any forum which helps in clubbing the old and new messages into one backup/ restore.