Comment 4 for bug 1216655

Not only InitSystem and InitConfig were replaced. Everything was converted to PEP-8-style names, and all apt_pkg.Get*() were converted to classes. There is a tool at /usr/share/python-apt/migrate-0.8.py that finds problems (It might produce false positives, but should find everything that needs to be ported).

The short porting guide is at:

  http://apt.alioth.debian.org/python-apt-doc/whatsnew/0.7.100.html#porting-your-applications-to-the-new-python-apt-api

and the table of old Get*() functions and the classes that replace them is at:

  http://apt.alioth.debian.org/python-apt-doc/whatsnew/0.7.100.html#real-classes-in-apt-pkg

You can also find this document in a local installation of python-apt-doc.