in reply to Tuta

I have a 4 year old Android phone that has not had updates for a while now. I am not going to use that as a basis for a secure IM system such as Signal.

I do not wish to buy a replacement for this phone. Neither Android nor iOS.

I use Wire IM. I believe it to be secure.

It has the great advantage over many IM systems in that you can register a personal account on Wire using just an email address.

Then you can chat and call using a computer.

Without needing a smartphone.