No Answer What does "Renewal delay" mean?

[frybread]

This is the description,

Input the number of days before license expiration where users are authorized to renew their license.

But forgive me, I'm a bit slow. If users let the license expire outside of this date, are they not allowed to renew?
And what does "0" mean? unlimited renewal days?

 

[Clement]

No no they are.
It's the delay, prior to the end of the license duration, where they start to have the right to renew.