Hi, I'm Dima, I was born in Belarus and now living in Berlin so I speak Russian, Belorussian, English, German and started to learn French some months ago.
I'm maybe the technical less skilled and the youngest one (not even 18) who got here on my own.
I've came in contact with Open Source when I was 10 years old and got my first laptop where my father, mainly system administrator, installed Ubuntu, which I don't like that much anymore. In that time I've really enjoyed the multiple desktops and especially COMPIZ.
Now I'm still using only FOSS (besides of Google Docs but it will be replaced with Nextcloud soon), Debian on my PC, Blender, OpenShot and Gimp for my "artwork", LMMS for music and so on.
When I bought my first smartphone half a year ago I've tried to do it right from the beginning and the first thing I've done was disabling any preinstalled app which I was allowed to and then downloading F-Droid and Orbot .
It took a while until I've found Kontalk because I've searched an alternative for WhatsApp but there's no string like "whatsapp" in the description and if you type "chat" you get 35 different apps .
After a month later I've learned what XMPP is, it got a little easier because there are only 8 (different+free) apps, where "XMPP encryption" has only ChatSecure, Conversations and Kontalk .
I've dropped the 2 first very quickly after I've seen that ChatSecure is way to complicated to use it with "normal" people and you have to pay for Conversations.
Thats where Kontalk was just pefect! Simple interface, easy (to use) encryption and entirely open!
Even those who don't know how to use the most simple functions in a web-browser are able to use it.
I really like Kontalk even tough the design isn't as cool as in WhatsApp or Signal but that's OK because it isn't the point.
The main feature I enjoy is of course the group chat in the beta.
The main feature I miss is sending of other file types, especially videos. Maybe you should be able to set up a server of one's own for this.
Keep going on!