SmugOx94

after having installed 

numpy==1.16

 in the first case or 

numpy==1.19

 in the second case. Is it correct?

Correct

the reason is simply that I'd like to setup an MLOps system where

I see the rational here (obviously one would have to maintain their requirements.txt)
The current way trains-agent works is that if there is a list of "installed packages" it will use it, and if it is empty it will default to the requirements.txt
We could have a flag (in trains.conf) saying, whatever you have in the requirements.txt , just ignore it.
What do you think?