I don’t know how you have installed HA, but for my Core install in VENV, I would find a copy of the MCP23017 component, here is a link (if it works) to one I pulled in Jan, core/homeassistant/components/mcp23017 at dev · Kdemontf/core · GitHub So put the mcp23017 folder, with the four files in it, in a folder in your congifuration folder, called custom_integrations. Then restart HA, it should pull it in if everything is still compatible. If you have trouble there is a few mentions of how to do this here (TLDR) as well. Removal of GPIO support - #27 by Reena