I was recently working on rewriting spacebar. A few things are already better tham with spacbar:

• sending messages works reliably
• no random crashes
• mapping of incomimg and outgoing conversations to contacts
• no more hacks to find the sim accoumt
• better design (imo)

however the app is not yet finished, most notably receiving message doen't work yet. I can't really say yet how much work fixing it will be. In case youare interested in workng in the new app instead, I can push the source code somewhere.

https://invent.kde.org/jbbgameich/spacebear

Spacebear progress update: Thanks to the help of Anthony Fieroni, spacebear now generally works (receiving and sending), work to invoke the client when a message arrives is work in progress and not fully tested, but should work as well.