Hi there - I too am having the same problem with a recent change to the order of my whatsapp chats - they used to be in chronological message order then about a month ago (end of November this year) they changed and no longer re- sort themselves back into chronological order according to the last message date remaining on the chat - they now stay in the order of last contacted NOT last remaining message date
I cannot see how to change this back and I HAVE contacted whatsapp TWICE and altho I received the standard acknowledgement reply to my messages i have not received any further reply from them since and its been 3 weeks since i contacted them !
All of the phones in my family have been affected in the same way by this change so its not just my phone - i am very keen to find out why this has happened as i would love to revert to the previous chat order as it suited me much better - so any help would be greatly appreciated - thank you xx