Error affecting edit posts

I had an error accuring as I tried to edit a page and turned on php messages upon errors.
This comes out (below) whenever I try to edit pages or posts until I turned off ‘My Calendar’.
Any idea what causes the plugin to create these errors? (Have them on every site where I use ‘My Calendar’ which I am quite fond of.

Thanks in advance
Mick

Fatal error: Uncaught ArgumentCountError: 5 arguments are required, 3 given in /customers/1/9/0/cm5lznu9s/webroots/04b27e78/wp-content/plugins/my-calendar/includes/post-types.php:463 Stack trace: #0 /customers/1/9/0/cm5lznu9s/webroots/04b27e78/wp-content/plugins/my-calendar/includes/post-types.php(463): sprintf('%1$s planlagt t...', 'feb 14, 2026 @ ...', 'https://hadersl...') #1 /customers/1/9/0/cm5lznu9s/webroots/04b27e78/wp-includes/class-wp-hook.php(341): mc_posttypes_messages(Array) #2 /customers/1/9/0/cm5lznu9s/webroots/04b27e78/wp-includes/plugin.php(205): WP_Hook->apply_filters(Array, Array) #3 /customers/1/9/0/cm5lznu9s/webroots/04b27e78/wp-admin/edit-form-advanced.php(212): apply_filters('post_updated_me...', Array) #4 /customers/1/9/0/cm5lznu9s/webroots/04b27e78/wp-admin/post.php(206): require('/customers/1/9/...') #5 {main} thrown in /customers/1/9/0/cm5lznu9s/webroots/04b27e78/wp-content/plugins/my-calendar/includes/post-types.php on line 463