Google is moving reminders to Tasks, any other calendar app with a similar feature?

So I got a notification that Google is going to retire the reminders feature from Calendar and make it a Tasks feature instead.

The only reason I was using Google:s Calendar app was for their reminders (and because they've made it impossible for third party apps to use reminders).

The most important part of reminders for me was the way they worked, by putting up a notification that didn't go away until manually dismissed. Very useful for important stuff like taking a medicine.

Any suggestions for other apps that have similar notifications? It would be great if they were a calendar app, and even greater if they are synced to a calendar over a standard (like CalDAV etc.) so I can self-host it.