Nothings changed. Still core code that dictates this: https://github.com/moodle/moodle/blob/MOODLE_31_STABLE/course/format/renderer.php#L431 and https://github.com/moodle/moodle/blob/MOODLE_31_STABLE/course/format/weeks/lib.php#L404-L422. Therefore nothing for me to fix.
And has been since Moodle 2.4: https://github.com/moodle/moodle/blob/MOODLE_24_STABLE/course/format/renderer.php#L140 and https://github.com/moodle/moodle/blob/MOODLE_24_STABLE/course/format/weeks/lib.php#L365-L383.
Thus I believe that you are mistaken and there was never an option with the weeks format. Perhaps you are confused with the topics format?