I'm glad I found this post. I've backed up the lib and vendor directories, downloaded root.zip and replaced the lib and vendor directories with the contents of root.zip. However, the pages stopped building and looking at /var/log/httpd/error_log, I see this:
[Thu Jul 05 17:21:33.451705 2018] [:error] [pid 25277] [client x.x.x.x:34052] PHP Fatal error: Call to undefined function mb_strlen() in /var/www/html/lib/MRU.php on line 143, referer: http://xxxxx... /index.php?m=home
I did a diff on the new MRU.php and the original one, and they are the same. No changes in the original and new file that contains the mb_strlen function (lib/phpmailer/class.phpmailer.php) either.