The upgrade was done via the extension manager.
I did enable error reporting but when I try the link I get the 500 error and no debugging is displayed. You can see the issue yourself at:
iaate.org (The only two links with that issue are Members Only/Members Directory and Join IAATE)
The only odd things I found when running the tools were the three plugins that are enabled but show in the plugins table as:
CB plugin "Business Listings": no database or no database description.
CB plugin "DT Register Records": no database or no database description.
CB plugin "My Events Posted": no database or no database description.
All the others pass the check.