The empathy version in the PPA is 2.27.5 of 3 August, which uses org.gnome.Empathy.StreamTubeHandler.x_vnc to call vinagre. The vinagre version is 2.27.90 of 17 August, which uses org.gnome.Empathy.StreamTubeHandler.rfb. This change has been done on 10 August. If I interpret the commit texts correctly, Empathy has been updated accordingly in version 2.27.91 on 25 August.
I guess updating the PPA to the latest empathy version should fix the problem.
The empathy version in the PPA is 2.27.5 of 3 August, which uses org.gnome. Empathy. StreamTubeHandl er.x_vnc to call vinagre. The vinagre version is 2.27.90 of 17 August, which uses org.gnome. Empathy. StreamTubeHandl er.rfb. This change has been done on 10 August. If I interpret the commit texts correctly, Empathy has been updated accordingly in version 2.27.91 on 25 August.
I guess updating the PPA to the latest empathy version should fix the problem.