"Catch up" não significa apenas "colocar o papo em dia". O contexto pode mudar isso. Inclusive o contexto da pergunta deste post. Além de "botar o papo" em dia, temos:
1. to go faster so that you reach the person or vehicle in front of you. [= alcançar]
We left before them, but they soon caught us up again.
Catch up with: If you hurry, you should catch up with them at the bridge.
2. to improve in order to reach the same standard or rate as someone or something
He's missed so much school that he's going to find it hard to catch up. [= pegar o rítmo, ficar no mesmo nível]
Catch up with: Pressure grew for salaries to catch up with inflation.
3. to do something that should have been done before [= recuperar, alcançar, acompanhar, "tirar o atraso"]
The deadline's tomorrow. How are we ever going to catch up in time?
Catch up on: I just want to go home and catch up on some sleep.
Catch up with: Staff are struggling to catch up with the backlog.
4. to talk to someone you have not seen for some time and find out what they have been doing. [= colocar o papo em dia]
Come over tomorrow and we can catch up.
Catch up with: I'll catch up with you another time, Kevin.
It'll give them a chance to talk and catch up with all their news.
Fonte: Dicionário Macmillan