Notices

it's strange, i have last version and always connect but xx seconds after, wu disconnects and several retry's after, red icon and error... And all day with this.
Some day, only during x minutes connects, sends and receive messages, but wu disconnects after

In my general experience, most of the "can't connect, even after updating" are trensient.
Once I update to the latest version, I always end up eventually having access again.

Re-registering doesn't seem a very good idea.
WhatsApp probably have code to detect too many attempts at registering same number again.

(Because I strongly suspect that's the behaviour WhatsApp expects from SPAMers. Thus, by trying to re-register at the slightest connection problem, WhatsApp might automatically flag you as a SPAMer.
Hence the weird answers from the WhatsApp costumer service: "Your number isn't a real mobile phone, but a VOIP number" or "Please send proof that this a mobile number you own by sending a picture of your SIM card and a copy of your phone bill", etc.)

Waiting out the outage and updating to the latest version seems to work better (never got rejected).

It has happened to me.
In my case, when it does, I've noticed that WU isn't the only application affected.
(seems to me that the DNS caching of the phone doesn't plays well with the DNS setup of some of Wifi networks I connect to).

Usually completely restarting the connection works for me.
(with GUI: enter Aiplane mode, wait timer, the return to normal connection mode, wait timer again.
with CLI: systemctl restart connman.service)

If yappari gets encrypted messages, could think WU will?
Until that time, we could use original whatsapp and return when update arrives?

I use WhatsUp for Jolla. If I was banned by the registration with my new phone number, can I write email on the WhatsApp-support to be unblocked?

We won't get a new version of Whatsup?

This version is working smoothly for me here

Worked fine few days, today went offline, and can't get wu online at all. Uninstalled wu same way as last time, re-installed same (latest) version, but no success. Damn..

Same here.
A few days ago, lost it and never came back.
Never used any other client (Android or iOS) except WhatsApp in N9 and Mittaakulu in Jolla.

It's simple they have you figured out. They can assign the numbers of the blocked folks to specific unofficial clients. They see that there's a huge fallback number after you asked them for clearance and an unban. The simplest thing they can do is ban you artificially and look for anomalies when you sign up again. Is that a possibility?

*paranoid*

TBH, I'd hope for a decline in WhatsApp usage from their policy. Maybe one day we get a proper native Signal/Textsecure compatible client, or something decent other than WhatsApp. WhatsUp was and still is the best usable client ( when it connects ;-) ) on both N9 and N950 and on SailfishOS. It's sad to see its current state with all the changes hammering down from WhatsApp and no community support. It happens to projects that only few contribute to.

Thanks to all who helped it get here!