It might have been attributed to an earlier goal that Apple shared with ANFR. But since this update covers a lot more then just a discontinued from sold iPhone 12 they have to be able to have a little wiggle room on their commitment.Once again (with feeling). The French authorities announced, in an official statement, that 17.1 would be out on October 24th.
Therefore, they lied.
Translated text:
This update has been released by Apple to some volunteer customers for a few days ("beta testers"). The company has committed to extending this software update to all French iPhone 12 users by October 24 at the latest