Good evening Jamie and welcome back!
Thank you for reaching out to us.
We are sorry to hear about the error message creeping up after the upgrade.
I would love to help you with this topic.
As a first troubleshooting step, could you please provide us with your complete system information in a private reply using the instructions found in the following link?
https://theeventscalendar.com/knowledgebase/sharing-sys-info/
Secondly, could you tell me if there is a /tribe-events/ folder located in your WordPress theme’s directory ?
Finally, does the problem disappear if you temporarily switch back to a default WordPress theme ?
Best regards,
Geoff B.