[SOLVED] Whatsapp delete/reinstall: Data?

WhatsApp Web has stopped connecting here. I can see the quick code square, scan it, but it never connects. By a process of elimination (~6 browsers over 4 Operating systems on the PC) I'm down to the WhatsApp application on the phone.

If I delete/reinstall that, where stand my contact & saved messages?

I chanced it. Read the FAQ.
First, I renewed my backup. Then I 'disabled' (=uninstall all updates & disable) the app, some of which was firmware. Then enabled it, updated it, and was all back where I was. But I STILL can't connect to whatsapp web :-o.

/Some time later

The new app is working now. Much fussier, but working. I can't actually delete the old app, because Samsung shipped it with their Android OS, but I could re-enable it, and then update it.