Ok, I took a look and the way you wish to do it copying the folders back and forth is a bit messy. It's best to just copy the files to a new folder and get rid of everything in this folder and upload the new files. I did backup the db to my hd.
I do notice that you have a restore manager in cPanel where you can restore your files, db's, and email by a certain date. So, I "assume" that there are daily backups. However, I do not see a way to do backups via cPanel except for how I do it. I just select what I wish to backup in File Manager and select "Compress" to zip the files up. I can "Extract" them whenever I wish or download it to my HD.
I downloaded your old forum zip dated feb 2014 to my hd and alos zipped everything today as-is...named forum.zip in your root folder.
If you wish me to proceed let me know. It should only take about 10 minutes or so to upgrade the forum and make sure all is right.