@x2ero I have 4.4.0 here. Maybe your distribution is stable or oldstable? From point of stability view, then sure the GTK-based version is more stable but lesser appealing. Otherwise I tried many other SIP software, like #Ekiga (not updated anymore?) and #Telepathy but doesn't work without KDE. Linphone so far had been working well. Finally also encrypted chat+file transfer works. I use @owncloud for file transfers, or rarely #Dino or even Linphone (I just did it there).