How long to transfer What’s app messages from old to new iphone

[Longchip]

My old phone smashed and won’t hold charge for more than a few minutes. It isn’t recently backed up to the cloud. I need to transfer my old what’s app messages to the new phone and was hoping to do this using the qr code method described here. faq.whatsapp.com/209942271778103/?cms_platform=iphone
How long will this take?
(I’m really scared of losing my messages because some are from my late mum.)

Bump…

I hadn't backed up my phone and lost all old WhatsApp messages when I moved to a new phone. Luckily not a big problem. I am still in groups etc and have contacts but all chats are blank. If you go into WhatsApp settings you can turn on chat back up which I think might save them?

I've just upgraded my iPhone and everything from my old phone transferred directly to my new one, will your old phone stay switched on when plugged in? All you should need to do is put them next to each other and it asks if you want to transfer it all. I've just checked and all my WhatsApp, email, and I messages are there from my old phone, in fact some of them are from the phone before!