Hello and thanks for choosing The Events Calendar! I’d be happy to help get your issue addressed. I do want to point out that the version you are attempting to revert back to is fairly old, so that may cause issues that can only be solved by using more recent plugin versions.
First and foremost, always make sure to backup before attempting any major updates on your site. With that said, take a look at this tutorial in our Knowledgebase on how to do manual updates. It’s clear, thorough, and should solve the problems you’re experiencing.
Please reply back and let me know if this article helps. If not, we’d be happy to continue troubleshooting for potential issues and remedies. Thanks again for choosing Pro and have a great holiday season!