Jabber stopped working after 6.7 update

I have just updated to 6.7, and Jabber does not seem to work any more. In the log, the connection is accepted:

=INFO REPORT==== 2015-10-20 11:51:08 ===
I(<0.367.0>:ejabberd_listener:281) : (#Port<0.4992>) Accepted connection {{192,168,1,4},12146} -> {{192,168,1,13},5223}

But my client (Vacuum) keeps saying "unknown host"
Any advice?

The update changed my hostname in ejabberd.cfg. Correctly adjusted, it works!