plugin upgrade

Maintenance updates for Calendar, WebDAV, 2FA, Email Scheduler, and Framework plugins, with reliability improvements, bug fixes, and updated AJAX handling.

Version 2.4 of the Roundcube Plus Calendar plugin is now available. This major upgrade closes a large number of security issues found during a thorough audit, rebuilds the front end on the modern Alpine.js framework, updates FullCalendar to the latest version, and fixes a wide range of functionality bugs. If you're running an earlier version, we recommend upgrading as soon as possible.

Maintenance updates are now available for several Roundcube Plus plugins, including the Email Scheduler, Last Login, Dropbox, and AI Assistant plugins. These are smaller updates that fix bugs and address a few rough edges.