On Sunday, 15 September, ATV-4 conducted a reboost for the ISS. Starting at 14:42 CEST, ATV Albert Einstein used two of its four main engines (OCS1 & OCS3) to lift the ISS into a slightly higher orbit.
After a burn of 205 secs, the velocity of the orbital complex was increased by 0.50 m/sec. The amount of propellant burned for this manoeuvre was 68.1 kg.
The next reboost using ATV is planned for 2 October 2013.
Thanks, Thomas Beck, at ATV-CC for the update!