Hi!
I'm trying that a number field it's automatically fill with the last number + 1
USERCASE:
It's for an association that they want to assign a number for every new submission.
The idea that I have is to found a way that with every new submission I have a code that check the last number that was created and then it add 1 and it fills the result in the new submission.
It is beyond the scope support of Meta Box but it can be accomplished by using custom code. Or I think you can create a text field then update its value after creating a post with the post ID because the post ID is also autoincremented and unique.