Stachethemes Event Calendar version 3.x will be the last version to use jQuery and the Wordpress AJAX API.
Therefore the next major release of the calendar will be build on React.js and will heavily use the WP REST API in favor to admin-ajax requests.
Some of the major changes that will follow with version 5 and onwards:
1) Calendar will use React.js in favor to jQuery.
2) Moving away from admin-ajax.php in favor to the WP REST API.
3) The calendar will use it's own drag & drop builder. Elementor builder will be removed.
Reasons for this: Elementor is great but is bloating the dom with unnecessary blocks for achieving simple things.
4) Dropping WPML support. WPML will no longer be required in order to translate events on multilingual websites. The plugin will come with its own built-in alternative.
Reasons for this: a) WPML is paid plugin. We want to minize the use of paid addons. b) Apparantly users find it hard to set-up.
5) Booking and RSVP systems will be completely re-designed.
It will be possible to link tickets and the rsvp feature of the calendar.
E.g. when customer purchase a ticket they will be automatically added as attendees.
Currently the two features work independently causing some confusion among customers.
... more details to come ...