[tor-relays] [WARN]Failing because we have 4063 connections already. Please read doc/TUNING for guidance

Hi all, since I upgraded the torland relay from 2.6.7 to 0.2.7.6 I get the following warnings: 09:20:30 [WARN] Failing because we have 4063 connections already. Please read doc/TUNING for guidance. [101144347 similar message(s) suppressed in last 21600 seconds] Google only spits out https://trac.torproject.org/projects/tor/ticket/16929 which does not help me. I don't find the mentioned branch bug16929 in git. Can someone please advise what has to be done to avoid the warning, or point me where I find can the file "doc/TUNING". Thanks torland