Saves created using COTL API 0.1.6 and below can be converted for COTL API 0.1.7 and above.
1. Upload file named 'cotl_api_data.json'. If you do not have it, that means you do not have a previous save using COTL API 0.1.6.
2. Converted file will be named 'io.github.xhayper.COTL_API.json'. Put it in the same folder as the other json file.
For Windows, you can find the old save "AppData\LocalLow\Massive Monster\Cult Of The Lamb\saves\cotl_api_data.json".
This converter is coded by hayper!