How safely to stop using backports repo?

[Sthu Deus <sthu.deus@gmail.com>]

Good day.

I have packages installed from backports repo. Now I want to remove the
repo from my source list and therefore use not any more packages from
there. My question is on security stuff, as AFAIK I can get into a
troublesome situation - in case of simply stopping using updates from
the repo - that in those packages bugs can be found but I will not get
updates for them - because: backports repo is no more available, and
the updates/security repos have updates but not for so high version as
the ones I have.

So, what is the secure and the easiest way of turning from using the
repo?

Thank You for Your time.