As a pre-requisite to deploy a new version of conftool that has the new extension for dbconfig, we should upgrade the fleet to use python3-conftool everywhere, as the latest conftool package (already deployed in part of the fleet) provides only the python3 version and dropped python2 support.
This is to avoid any issue with the double upgrade/migration from python-conftool to python3-conftool with all the additional changes that will be included in the new release.
This is the current list of hosts with the python2 version (589 as of now):
https://debmonitor.wikimedia.org/packages/python-conftool