Hello Joël,
Thanks for writing to us
Our theme is compatible with Modern Events Calendar version 5.9.0. The 5.10. is just released by the MEC developer a few days ago. We are currently testing the latest version of all plugins for compatibility with our theme and these will be released after it has passed our test.
Please review our Version Compatibility https://theme.co/docs/version-compatibility
Please ensure your theme is validated so Extensions can be installed automatically
Deactivate and delete the extensions, from the plugins panel.
On the X > Validation > Extensions locate and install the extensions that you need.
Visit the “Plugins” panel in your Dashboard to activate the newly installed version.
Hope it helps you.
Thanks