How to not upgrade a package while using APT
Context
This can be a desirable behavior (in some very particular cases). Note here that I do not recommend this in general.
However, in my case, it's been a need as the rmtfs package was crashing my mobian little server.
How To
APT has a built-in way to hold a package and not update it further :
sudo apt-mark hold <packageName>
Giving this :
$ sudo apt-mark hold rmtfs
rmtfs set on hold.