732
Signal and Threema want nothing to do with WhatsApp
(www.androidpolice.com)
This is a most excellent place for technology news and articles.
I believe Matrix doesn't have nearly as strong (if any) metadata encryption as Signal
Unfortunetly no. Can be shown when you reset the encryption keys, relogin and see that times of messages, who you are talking with and even reactions are visible. But I know for reactions and replies they are working on it.