tmux (1.4-7) unstable; urgency=low

  Starting with version 1.4-7, tmux is no longer installed setgid utmp and
  server sockets are no longer placed under /var/run/tmux, reverting to
  the default upstream behavior (sockets in a user directory under /tmp).

  We recommend that you close any open tmux sessions before proceeding
  with the upgrade. If necessary, old servers can be accessed after the
  upgrade with e.g. "tmux -S /var/run/tmux/tmux-`id -u`/default attach".

 -- Romain Francoise <rfrancoise@debian.org>  Sat, 16 Apr 2011 19:16:23 +0200

tmux (1.3-1) unstable; urgency=low

  Due to an update in the server protocol from version 5 to version 6
  users need to terminate open tmux sessions before proceeding with
  updating tmux 1.2 or older.

 -- Karl Ferdinand Ebert <kfebert@gmail.com>  Fri, 23 Jul 2010 08:09:03 +0200