I updated from the PPA last week and noticed the html5 client no longer works. I just get an empty white screen instead of windows loading. I was able to fix this by copying the /usr/share/xpra/www folder from a system that had a prior working install on it.

A hint may be here:

Files www.broken/connect.html and www/connect.html differ
Only in www.broken: connect.html.br
Only in www.broken: connect.html.gz
Common subdirectories: www.broken/css and www/css
Only in www.broken: favicon.ico.br
Only in www.broken: favicon.ico.gz
Files www.broken/favicon.png and www/favicon.png differ
Common subdirectories: www.broken/icons and www/icons
Files www.broken/index.html and www/index.html differ
Only in www.broken: index.html.br
Only in www.broken: index.html.gz
Common subdirectories: www.broken/js and www/js

xterm started as application session on the remote server runs with umask 0000. This has security impact as files/directories created by users are then world-writable. Expected: some sensible default like 002 or 022.

Version: winswitch 0.12.23-1, xpra 2.1.1-r16658-1

Possible cause: winswitch server assumes umask will be set in /etc/bashrc. That is true on Red Hat derived systems. But it is not true on Ubuntu (tested 16.04 LTS) where I think umask is expected to be set by PAM session (pam_umask.so).

Perhaps related, the PAM file provided by /etc/pam.d/xpra seems to assume a Red Hat style system and most of the PAM modules referenced there do not exist on a Ubuntu system.