Tmux – Default Window Names in Status Bar

On one of my clients' servers, I've been using the tmux status bar to monitor long-running processes, both through the automatic window-name changes and by setting window names through ANSI control codes in scripts. It's incredibly useful when you have to run a dozen processes at a time and see which ones are finished.

They recently moved the server to a new provider (Amazon AWS, I believe), and suddenly tmux is crippled. There's no automatic name-changes on the tmux status bar, and it won't respond to the scripts' name-changes (it does respond to some script changes, I'll have to work out why it isn't doing all of them).

I've tried various configuration changes, but nothing seems to make a difference — the "name" is always X:login@hostname:workingdir (where X is the window index).

Am I doing something wrong, or is it a limitation of the server? In either case, is there some way to fix it?

Here's my current .tmux.conf file:

set -g xterm-keys on
#bind-key C-b last-window
set -sg escape-time 20
setw -g mode-keys vi

# Reload the config file on demand.
bind r source-file ~/.tmux.conf

set -g set-titles on
setw -g allow-rename on
#setw -g monitor-activity on
setw -g automatic-rename on
setw -g window-status-current-format "#I:#W#F"
setw -g window-status-format "#I:#W#F"

Old system: CentOS 6.10
Old tmux version: 1.6
New system: CentOS 7
New tmux version: 1.8