Blank Web Pages after Update

After I updated two modules about two days ago, I can no longer access the Web GUI. When I attempt to access the web GUI, the initial login screen shows, where I entered the username and password. However, it won’t load the rest of the GUI and I am left with a blank screen. The system otherwise seems to be functioning (phone calls work).

This is similar to a problem that occurred about to two years ago in this thread:

However I don’t seem to have the same log file on my system.

I tried to update the system using the command line with:
sudo -u asterisk /var/lib/asterisk/bin/module_admin upgradeall

However I received the following error:
PHP Fatal error: Call-time pass-by-reference has been removed; If you would like to pass argument by reference, modify the declaration of logfiles_highlight_asterisk(). in /var/www/html/admin/modules/logfiles/ on line 133

Any suggestions on the best solution for this problem?

After a bit more searching I found out that it is a known bug with a solution here: