@xIExodusIx that’s due to changes in the handling of the python packages. I installed “fritzconnection” in a virtual environment:
python -m venv venv
source venv/bin/activate
python -m pip install fritzconnection
to make the Callmonitor use the fritzconnection, I edited the nodehelper.js (in ~/MagicMirror/modules/MMM-FritzBox-Callmonitor-py3) in line 212 to look like this (user is “pi”, must be adapted if you use another user):
pythonPath: '/home/pi/venv/bin/python',
Don’t know if it’s the best solution, but it works.