My whatapp contact updated their phone number and retained all chat history seamlessly. However, on the other hand, even after updating the telephone number of my contact in my iPhone, I have 2 chat threads. One with the old number my contact used to use and the other with the new number. I am not able to find a solution to retain all chat history for my whatsapp contact when the contact's number is updated.
Seems odd that the help provided is only to migrate history while the recipient of chats does not have the option to retain or migrate the history like the person updating the phone number.