Meaning of “latest” - Learner’s Dictionary

latest

noun uk us /ˈleɪtɪst/
the latest in sth

the most recent of its type:

This is the latest in a series of terrorist attacks in the region.
at the latest

If you tell someone to do something by a particular time at the latest, you mean they must do it before that time:

She said to be there by 8 o'clock at the latest.

(Definition of “latest noun” from the Cambridge Learner’s Dictionary © Cambridge University Press)