I think a lot of this debate argues for the sysadmin role being part of the dev team. The only real way to get both constraints (production stability and update to date fixes/features) is to have fast feedback between the interest holders of two sides.

In the python-specific case -- the requirements.in / .txt files for the virtualenv should be part of the software VCS, but the sysadmin should be able to edit & pin things just like the devs, so that they can bring their expertise to the container, rather than having to fight it.

---

Mind you, my opinion might not scale - I'm part of a small enough team that I'm holding both those roles, but I try make sure to spent time wearing both "hats", so that one role doesn't get more man-hours clocked.