So, since noticing that the 3.4.0 client destroys timestamps and syncs over and over, I decided to see what the current release was on your downloads page…
3.3.6 is now currently the latest stable version. Don’t think theres been an official communication of this as well as stopping auto upgrades to v23 server…
Not great nextcloud devs… in fact pretty amateur. 
What do you think they should have done instead? Continue to offer the buggy version, so that even more people install it and then potentially have issues. Yes the situation is less than ideal and this shouldn’t have happend in in the first place. But removing the buggy version and offering the old version again was their best option in order to limit any further damage.
Btw, If you want to help with testing the bugfix release, you can…
What do I think they should have done instead?
Put out an announcement that is easily visible, informing people of such a major bug and the actions currently taken to mitigate its impact whilst they work to resolve.
There are none at the moment, except for the downgrade. But I agree with you, that an announcement on their website and a sticky in the forum, would be useful for those who have already installed or upgraded to it,
They have already taken mitigating actions by removing the bad version… Thats what I meant.
Yeah that’s what I meant too. Sure they could spread red banners all over their website to communicate this. But no company really does that.
There are three possible scenarios:
If 1 or 2 applys to you, you are fine and you don’t really need an annoucement.
If 3 applys, an anouncement on the download page wouldn’t help you either because you already downloaded and installed it and then you would most likely come here, where a sticky indeed would be helpfull 