BTW vexl isn't based on nostr, so your comment is off topic in this thread. That said:

It would be nice to have flags on notes that mark the status of the note. Like expired (user could set a flag with a condition of crossing a certain date or any other parameter, that would switch the asigned flag on). But also a flag that says "old version of the note, the updated one is -note id link-". It is hard to delete a note on nostr, but this way one could be able to correct mistakes in a new note and link it to the old note in obvious way. Preferably nostr clients would display it in some intelligent way (as a vesions of the same note).