The latest version of HA core has made some breaking changes which affects a number of integrations, one of which is Foxess Modbus.
Don't update just yet (if you have downgrade using the Terminal command ha core update --version 2023.12.3 )
Work is on-going and hopefully there will be a fix by 7th Jan 2024 - but also note this may break some of your other integrations so double check their function at startup.
