(IANAL)

Since the software is already distributed under the terms of the GPLv3 (which guarantees irrevocable rights) there is no way to forbid any distribution of the current version of the software.

It is however possible to distribute future works under a different license, but only if you aren't bound by the GPL yourself. This would be the case if you wrote the code yourself or all contributors grant you the right to do so (eg. using a Contributor License Agreement).

Once someone exists publicly as code with an attached valid license it cannot be retroactively removed the right to use it. So only new versions could have different licenses or something.

Well no, it's factual: the man very generously did invaluable work for years. And then he sold out. That's just what happened, however grateful I am to him for the work he did for all those years.

I assume there were no other companies willing to buy Simple Mobile Tools, otherwise he wouldn't have sold to that particularly hateful bunch of sumbitches. One doesn't provide free tools with total abnegation for so many years and then choose the worse possible buyer this side of the law without a good reason. So I accept his choice and his reasons - whatever they may be.

But surely there were other ways to handle this. Like for example, telling the community that money has run out and he will be forced to sell to unsavory characters, and appealing to the community to fund him if they wanted to keep Simple Mobile Tools ads-free. But instead, he went about it all hush-hush and sprang it on everybody - users and contributors alike. Not cool.

Finally, remember that some people actually paid for their copies of Simple Mobile Tools, and they paid precisely to prevent this happening. They must feel pretty betrayed, and rightfully so.

he is selling his app suite to a comany known to ruin apps with trackers and ads, making the simple mobile tools suite no longer simple, but just another app in the ocean of crap. Also he likely violated liscences doing so

he could have at least sold to a better company, and considered the wishes of his fellow contributers as he have should according to his liscence

I've tried it a few times in the past but have always come across bugs that give me functional issues. I can't remember exactly what they were right now but give it another few months and I'll probably try it again.

Wondering if ConnectYou will work with my contact list in NextCloud.